The computer turns on spontaneously. The computer turns on by itself: how to solve problems related to turning on

Recently they brought me a computer for diagnostics, which turns on itself when connected to a power outlet. There may be several reasons for this phenomenon - from simplest mistake in setting up the BIOS, to a hardware malfunction, sometimes leading to expensive repairs. First of all, in this case, you need to find out - after which the computer began to turn on on its own, without the need to press the “Power” button. For example, in my case, after much questioning, I found out that the day before the client’s grandson was sitting at the PC and doing something “in the blue table.” That is, some BIOS parameters were changed. The problem was resolved in a few minutes and the client left happy.

Reason 1. Special function in BIOS

This is the main reason why the computer turns on by itself immediately after being plugged into the power supply. It is turned on and off on the motherboard, namely in the “Power Configuration” or “Power Management” section. There should be a setting called "After AC Power Lost".

Also, depending on the board manufacturer and BIOS version, the parameter can be called:

After AC Power Failure Restore on AC Power loss AC Power Loss Restart AC Loss Auto Restart AC PWR Loss Restart Power Again Power On After Power Fail Power Failure PWRON After PWR-Fail Power State Resume Control System After AC Back State After Power Failure

This parameter responds to the computer’s reaction when power is connected to it and has several meanings:

— Stay Off(or just Off) — the computer will remain turned off and will not react in any way;

— Power On(or just On) - the computer will automatically turn on when voltage appears in electrical network;

— Last State(or Previous State) is the last state. If this option is selected, the behavior of the device when plugged into an outlet or power supply appears will depend on the state of the computer at the time of the power outage. That is, if it was turned off, nothing will change, but if it was turned on, it will turn on again.

So, if you don’t want the PC to turn on when plugged in, set the value to “Stay Off”.

Reason 2: Hardware failure

Unfortunately, in some cases, the computer’s autostart when power appears indicates that the computer’s components have failed.

The power supply is broken

Often on cheap Chinese blocks There are so-called “breakdowns” in the power supply, in which the PC turns on independently from an electrical impulse, without pressing the “Power” button. If you have such a power supply, then I strongly recommend replacing it before it’s too late, otherwise next step The motherboard may break down, and this is already a significant expense.

Motherboard failure

This is the worst of possible options and the most expensive. As a rule, spontaneous switching on computer (autostart) in this case means problems with the power supply. It can occur both on old motherboards due to swollen capacitors, and on new ones due to manufacturing defects.

P.S.: If surges and drops in the electrical network often occur in your home, then mandatory It is necessary to install a voltage stabilizer. Otherwise, even if you replace components due to a malfunction, then after short time The problem will happen again and you will have to change the power supply or motherboard again.

The operation of a computer depends on the coordinated interaction of hardware and software, and not only operating system installed on a PC, but also basic system I/O – BIOS. One of the problems that users may encounter when the interaction of computer components is disrupted and for other reasons is the spontaneous turning on of the system unit. This problem is more relevant for desktop PCs than for laptops, and in this article we will look at the main reasons why the computer turns on by itself.

Computer turns on spontaneously due to hardware problems

The most common problem that causes the computer to turn on spontaneously is a malfunction of the power button. Most often, the power button is located on the front panel of the computer, and it is enough to press it to supply power to the PC components and start the system booting. But wear and tear on the power button or oxidation of its contacts can lead to the computer turning on spontaneously.

Making sure that your computer turns on by itself due to a faulty power button is quite simple. You need to disconnect the button from the motherboard; most often it is connected by two contacts that fit the pins labeled PWR (Power) on the board. Disconnect the power button and observe the behavior of the computer when it is turned off. If it no longer turns on by itself, this indicates a malfunction of the button. The faulty button must be replaced or its contacts cleaned if they show signs of oxidation.

Another hardware problem that can cause the computer to turn on without the user pressing the Power button is the power supply. Some models can turn on the computer when voltage appears if their power button is set to “On” mode. To determine whether such functionality exists on your computer, you need to read the instructions for the motherboard. Most often, this problem is associated with BIOS settings, and below we will talk about what exactly to disable in them to correct the situation.

Computer turns on spontaneously due to software problems

The computer may turn on by itself due to BIOS and Windows settings; we will consider each option separately.

BIOS

The BIOS has a number of settings that allow you to turn on the computer in one way or another without pressing the power button, even if it is not in sleep mode or hibernation mode. Depending on the BIOS version, the names of the settings discussed below may vary, but they are available in almost all basic I/O systems.

The following settings in the BIOS can lead to the computer turning on spontaneously:

If you cannot find one or more settings in your BIOS that may affect the computer turning on spontaneously, you can simply reset the base system settings to the “default” option. This is done (most often) by pressing the F9 button in the BIOS environment. You can also reset the BIOS to default values by removing the battery from the motherboard for 20-30 minutes.

Windows

Some operating room settings Windows systems can also cause the computer to turn on spontaneously. The first step is to make sure that the power button turns off the computer and does not put it into sleep or hibernation mode. To do this, go to the “Control Panel”, select “Power Options”, in the left part of the window select the “Actions of the power buttons” section and in the window that opens set the computer to shut down when you press the power button.

Another setting you need to configure in Windows to prevent your computer from turning on by itself is the Wake Timer. Go to the settings of the selected power plan and additional parameters power supply, make sure wake-up timers are disabled.

Random turning on of a PC or laptop is most often associated with hardware faults. These include problems with the power switch and shorting of the wires connected to it. Among software errors causing the PC to turn on without user intervention - incorrect settings BIOS settings and Windows Power Options.

Power button malfunction

The most common reason, by which the computer turns on on its own - problems with the power button on the device body. At normal operation, pressing it causes the contacts to close, which turns on the power of the device. But if the button is broken, the shorting may occur randomly, without the user pressing it. For example, closely spaced jumpers may touch each other due to chassis vibration caused by movement in the room.

To diagnose problems with the power switch, follow these steps:

Disconnect the computer from the electrical outlet.
Open the side cover of the housing.
At the bottom of the motherboard, find the “Power SW” connector and remember its location.
Check the integrity of the cables connecting the connector and the power switch.
Disconnect the connector.
Close system unit and plug the cord into the outlet.

After that, leave the computer and wait for the next time it turns on on its own. If it does not work, the problem was caused by a broken button. You can purchase a new switch yourself at a computer store. Replacement is easy to do at home.

Pay attention! If the cable insulation is broken, a short circuit may occur in this place, as a result of which the device turns on automatically. You can restore a damaged winding using insulating tape.

Useful video: The computer turns on by itself, what should I do?

Incorrect BIOS settings

The computer may turn on on its own if the Basic I/O system settings are set incorrectly. To change them, when you turn on the computer before the operating system loads, press the DEL key until the CMOS setup menu appears on the screen. Using the arrow keys on your keyboard, navigate to the "Power Management Setup" section and press Enter.

Set the value to “Disabled” in the following points:

Power On by Alarm;
Power On by Mouse;
Power On by Keyboard.

Press the F10 key and confirm saving the settings.

Advice! Some BIOS versions have an “After AC Power Failure” option. If this section is present, also set it to “Disabled” so that it does not turn on automatically.

Important video: Another reason for the system unit to turn on spontaneously

Alternative shutdown method

If the PC continues to turn on on its own, it is recommended to take the device to service center. Problems may be related to the power supply of the motherboard. You can temporarily use the button on the power supply to turn off the computer without unplugging it. It is located on the back of the case, under the input for the power cable.

The trouble described in the title of the article sooner or later happens to every computer: one day it stops turning on. Sometimes this is preceded by some event, and sometimes absolutely nothing. In some cases, such failures are corrected very easily, while in others they are difficult to fix. In short, the range of problems that lead to a PC not turning on is very wide. Let's talk about them in more detail: what causes them, how to find the cause and deal with the problem yourself, without resorting to the help of specialists.

When someone says that their computer does not turn on, know that by this complaint the owner may mean the following:

The PC really does not turn on: there is no response to pressing the power button at all.
The PC turns on, but not completely: sometimes this is limited to the inclusion of indicators on the system unit and keyboard, sometimes to the sounds of the system speaker, sometimes when you press the power button, the fans start working, and then nothing happens. General detail one - the screen remains black.
The PC turns on and immediately turns off or goes into an endless reboot until the picture appears on the screen.
The PC turns on and works, but the operating system does not start on it.

The first 3 situations are of hardware origin, that is, they are associated with a malfunction or incorrect connection of the equipment. The latter is most often caused by operating system errors, which arose, for example, due to unsuccessful Windows updates 7 to Windows 10, as well as device driver failures. In the case of drivers Windows startup usually interrupted by a blue screen of death - BSOD.

In more rare cases, the inability to boot the OS is also associated with hardware problems - usually RAM or a hard drive.

Reasons for true non-inclusion

Since failures to load operating systems are a separate big topic, we will not dwell on them in detail. Let's look at the reasons for the first three situations and, in addition to them, one more: turning on the computer not the first time, but after repeatedly pressing the power button. So…

The computer does not respond to the start button

No power from the mains (the outlet or device through which the computer is connected to the power source does not work - a UPS or surge protector). The only reason not related to a PC malfunction.
The power supply does not produce the required voltages because it is faulty, insufficiently efficient, or not powered from the network due to a damaged electrical cord.
Poor contact in device connectors, damage to power cables inside the system unit.
Low battery voltage for BIOS chips.
Short circuit in one of the devices.
Malfunction of the switching circuit elements on the motherboard.
The power button on the system unit is faulty.
Blocking switching on by static charge.

The computer does not turn on completely (no initialization)

The elements of the video subsystem are faulty (video card, monitor, video cable). The absence of an image on the monitor, even if everything except video is working, in the eyes of the user looks like the computer not turning on.
The BIOS firmware has crashed (on some laptops, the BIOS crash is manifested by a complete lack of response to the power button).
The board has a faulty or unsupported processor installed.
The processor power supply system (VRM) is faulty.
Faulty RAM or its power supplies.
On old motherboards - failed north bridge or bridge power.

The computer turns off immediately after turning on or reboots cyclically early in the startup phase

BIOS meeting.
Overheat.
RAM defects.
The same reasons as for the complete lack of response to the button.

The computer turns on only after pressing the button multiple times

If the machine is older than 5-7 years, the life of the electrolytic capacitors in the power supply, on the motherboard or devices connected to it is exhausted.
The power button is faulty (the contacts are coming off).
Elements of the circuit starting the board or powering high-load components are faulty.

Diagnosis at home

Home users typically do not have equipment that can make troubleshooting easier, so they are left with the use of their senses and spare, known-good parts.

Before starting a diagnosis, it is important to remember what preceded the problem and what could have caused it. For example, the computer suddenly turned off during a thunderstorm and will not turn on again. Reason: burning out network controller high-voltage lightning charge through twisted pair. If it stops turning on after some manipulations in the system unit - connecting a new device, cleaning it from dust, etc., the reason is most likely due to incorrect assembly or broken contacts of the devices.

If there is no obvious cause-and-effect relationship, for example, yesterday you turned off the computer as usual, but today it did not turn on, start checking with external contacts— the cord of the power supply, monitor and everything else that is located outside. In such cases, the following technique often helps: turn off the machine from the outlet or using the key on the power supply (i.e., disconnect from the power source) and hold down the power button on the system unit for 20-30 seconds. This will remove the static charge accumulated inside, which sometimes blocks starting.

Narrow it down possible problems the squeak of the system speaker helps: decoding sound signals easy to find on the Internet. But keep in mind that BIOSes different manufacturers“squeak” differently. If the computer does not beep at all, it either does not have a speaker, or due to a malfunction (usually the power supply or motherboard) it is not running the BIOS microcode.

In cases where you cannot decide where to “dig”, use the algorithm that we present below. After each diagnostic step, try turning on the computer.

Inspect the system unit and all its connections from the outside. Disconnect unnecessary peripherals and everything connected to USB, except the keyboard and mouse.
Remove the cover of the system unit and make sure the internal connections are secure. If there is any accumulation of dust, remove it. If motherboard older than 3-5 years, replace the BIOS battery (brand CR-2032, sold in kiosks).

Without pressing Power buttons on the system unit (with the power supply connected to the network), if possible, check whether standby power is supplied to the motherboard (for example, Asus has a standby LED indicator). Check by hand the temperature of large elements of the motherboard, video card and expansion cards. Normally they should be cold or slightly warm. If any part becomes noticeably hot, it is very likely that it is the source of the problem.
Turn on the power of the system unit. Pay attention to how the fans behave. Normally, after spinning up, they should slow down a little. If you see exactly this picture, the reason that there is no image on the screen is 80% likely to be a problem in the video subsystem. If the coolers are operating at maximum high speed, the reason is a failed BIOS, a “broken” RAM, a non-working/unpowered processor or a north bridge (on old motherboards). If the coolers make several revolutions and stop or only have time to jerk once, the source of the problem is a short circuit on any of the devices or poor contact at their connections. Cycles of spin up and stop running one after another (rebooting the computer at an early stage of startup) are usually due to damage to the BIOS. If the fans are not spinning at all, they are most likely not receiving power. This often happens when the power supply or motherboard is faulty.

If there are no signs short circuit(when they are, further diagnostics should be continued only after it has been eliminated), turn off the computer's power and reset the BIOS settings to default.

If the above algorithm does not clarify the situation, it is more convenient to continue further diagnostics on a stand assembled on a table.

Assembling the stand

Before removing components from the case, do not forget to turn off the power to both the system unit and the monitor - turn off the surge protector or unplug the cords from the outlet. If the computer is powered by a UPS, simply unplugging it from the outlet is not enough, since the batteries still have a charge.

Next, prepare workplace. The table on which you will assemble the stand must be dry and clean. It is not necessary to use special antistatic mats; it is enough that there is nothing metal on the table. To avoid damage electronic components static from your body, it is advisable to wear an antistatic wrist strap. If it’s not there, it’s okay: just touch any unpainted part of the PC case with your hands.

When removing each part, inspect it for:

chipped elements;
integrity of contact groups (presence of broken and bent contacts, melted or darkened plastic pads from overheating);
deformed and defective components (swollen capacitors, traces of leaked electrolyte, microcircuits with stains, and even more so burnout holes);
darkening on PCB (with reverse side yellow or brown spots often appear on boards under very hot elements).
scratches (if the scratch is above the tracks, look at it under a magnifying glass with maximum magnification to make sure that the tracks are intact).

Any of the listed defects may cause the PC to not work.

On machines that turn on for too long, every other time or after multiple reboots, pay special attention to the capacitors and the condition of the PCB underneath them. Thus, electrolytes that have outlived their useful life may look normal, indicating a malfunction only as a small dark spot on the back of the board.

If there is any suspicion of the unsuitability of electrolytic capacitors, they should be replaced with new ones, and not only obviously defective ones, but all those that are in the same circuit with them.

Having finished inspecting the devices, assemble a stand with minimal configuration on the table. For a test run, all you need is a motherboard with a processor and a cooler, one memory module, a power supply, a keyboard and a video card (if you are using a discrete one and the processor or board has built-in video, connect the monitor to the latter).

When assembling the stand, it doesn’t hurt to clean the contact combs of the RAM and expansion boards with a school eraser. This will remove oxide deposits from them, which worsens contact in the connectors.

Turn on the power supply (if it is working properly, the board should start receiving standby voltage). Check the temperature of the components again with your hand. It should not be hot, as you remember, normally.
If you are in doubt about the functionality of the power supply, replace it with a known good one (if available). If this is not the case, try running it separately from the system: disconnect the 24-pin connector from the motherboard and connect a load, for example, an optical drive or a regular light bulb with soldered wires, to one of the free connectors. On the block that connects to the motherboard, close the contacts opposite the green and one of the black wires. If the load shows signs of “life” and the fan in the unit itself starts spinning, you can consider it conditionally operational.

To avoid electrical injury, do not open the power supply, even if it is turned off. Capacitors in the high-voltage part of its circuit can retain a charge for quite a long time.

Start the stand (remembering to return the working power supply to its place). This time not from the power button, but by closing the contacts to which its wires are connected on the board. If a picture appears on the screen (the computer is working), the cause of the problem is in devices that are not currently connected to the stand. If a monitor that is known to work does not turn on, the failure occurs due to the fault of one of the devices involved.

How to identify a problem node using indirect signs

If your computer has several memory modules, try running the test bench with each one in turn, installing them in different slots. If one of the combinations works, update BIOS firmware. After this, perhaps the rest of the memory will work.
If none of the RAM modules made the stand turn on, try running it without memory at all. In this way you will check the conditional “liveness” of the BIOS. “Live” firmware will make itself known by the squeaking of the system speaker or the blinking of indicators on the keyboard or motherboard.
Install a known-good and compatible processor on the bench. If the computer turns on normally, update the BIOS. Perhaps the processor that was installed before was simply not recognized by the system.
If you are using discrete video card, check it in different slots (if available), and also connect it through another video output to another monitor input.
If everything described above does not help you identify the source of the problem, the culprit is most likely the key component - the motherboard.

What to do with the device that caused the failure? The choice is small: replace it with a new one or take it to a service center for repair.

Even when computer users have a stable operating system and the vast majority additional programs, difficulties may still arise. Such problems can rightfully include spontaneous turning off and turning on of the PC, regardless of the user’s actions. It is about this, as well as about ways to eliminate faults of this kind, that we will discuss in detail later in this article.

First of all, it is important to make a reservation that difficulties with automatic switching on power failure of a PC or laptop may be due to mechanical faults. However, diagnosing power failures can be overly complex for a novice user to understand, but we will try to shed enough light on this problem.

If you encounter difficulties not covered in the article, you can use the comment form. We will be happy to help you.

In some, as real-life practice shows, the most common cases, problems with automatic activation can also come directly from the operating room Windows systems. In particular, this affects users whose computers are not adequately protected against virus programs and are rarely cleared of various OS overheads.

In addition to all that has been said, we recommend that you study each side instruction without fail, regardless of the actions described. This approach will help you get rid of the problem that appears with the system turning on spontaneously without unnecessary difficulties.

Method 1: BIOS Settings

Quite often, users of fairly modern computers have difficulty turning them on automatically due to incorrectly configured power supply in the BIOS. Here it is important to place special emphasis on the fact that in the vast majority of cases this difficulty arises precisely as a result of incorrect setting of parameters, and not mechanical breakdowns.

Users of old computers equipped with outdated power supply models may not encounter this problem. This is due to radical differences in the process of transmitting electronic impulses from the network to the PC.

Using an outdated PC with AT power, you can safely skip this block recommendations, moving on to the next method.

If you are the owner modern computer, which has an ATX power supply, then you should do everything exactly according to the instructions, taking into account the unique features of the motherboard.

Try to find out in advance about all the features of the equipment you are using.

Moving directly to the essence of eradicating the problem, you need to pay attention to the fact that literally every motherboard has a unique BIOS. This applies equally to both the number of parameters and limitations in various capabilities.

Follow the link we provided to familiarize yourself with the methods of transition to BIOS settings and open it.

The computer BIOS itself may be very different from what is shown in our screenshots as an example. However, be that as it may, you should be guided solely by the names of the menu items mentioned.

In some cases, you may need to go to a special tab "Power", on which all parameters related to power supply are located separately.
Through the presented BIOS menu go to section "Power Management Setup", using the appropriate keys on the keyboard for navigation.

Toggle option "WakeUp by Onboard LAN" to mode "Disable" to prevent the PC from starting after receiving certain data from the Internet. This item can be replaced by "Modstrong Ring Resume" or "Wake-On-LAN".

To limit the impact of the keyboard, mouse, and some other types of devices on your PC's power, turn off the "WakeUp by PME# of PCI". This point can be divided into "PowerOn by Mouse" And "PowerOn by Keyboard".

The last rather significant section is the functionality of delayed startup of the computer's power supply, which, by the way, could be activated by malware. To get rid of the problem of spontaneous startup, switch the item "WakeUp by Alarm" in a state "Disable".

The section is interchangeable with items "RTC Alarm Resure" And "Power On by Alarm" depending on the BIOS version on the motherboard.

After following the recommendations we have presented, do not forget to check that the computer shutdown system is working properly. Please note that the entire list of actions above is equally suitable for users personal computers and laptops.

The BIOS of laptops works on a slightly different principle due to the different structure and power supply of the device. This is why laptops are often much less susceptible to problems with automatic shutdown or turning on.

Once you have completed setting the desired settings in Computer BIOS, save the settings using one of the burning keys. You can find a list of keys on the bottom panel of the BIOS or on the right side.

In case of malfunctions due to any changes, you can always return the values of all parameters to their original state. Usually the key is reserved for these purposes "F9" on the keyboard or is special item menu on a separate tab. Hotkey may vary depending on the BIOS version.

Sometimes updating the BIOS to the latest one or more can help solve problems with the BIOS. stable version. You can find out more details about this in a separate article on our website.

Please note that some settings may revert to initial state independently due to the influence of virus software.

If after restarting the computer the spontaneous startup stops, this article is considered complete for you. But if there are no positive results, you should resort to other methods.

Method 2: Sleep Mode Problems

At its core, computer sleep mode also relates to this topic, since at this time the system and equipment are in an inactive mode. And although the PC’s input means are turned off during sleep, there are still cases of spontaneous activation.

Don't forget that sometimes hibernation can be used instead of sleep.

Ideally, the state of the computer in sleep mode or hibernation remains unchanged, regardless of any nuances. In this case, the user only needs to press a key on the keyboard or move the mouse to start the awakening process.

Therefore, first of all, you need to check the functionality of the connected input devices. This is especially true for the keyboard and possible mechanical sticking of the keys.

In order to resolve all possible difficulties, disable sleep and hibernation mode using the appropriate instructions on our website.

Please note that the sleep itself can be configured differently depending on the version of the Windows operating system used.

For example, the tenth version has a unique control panel.

However, some versions of the OS are not very different from other editions of this system.

If it becomes necessary to roll back changes, you can enable sleep or hibernation mode, returning all changed parameters to their original or most acceptable state. To simplify the process of making these types of changes, and also familiarize yourself with additional methods To turn on sleep mode, read the corresponding instructions.

On this, in fact, we can finish the analysis of malfunctions that are in one way or another related to the automatic exit of the computer from the sleep and hibernation state. However, remember that the reasons and solutions may be unique for each individual case.

Method 3: Task Scheduler

We touched upon the use of the task scheduler earlier in one of the already mentioned articles, but in the reverse order. Check availability unnecessary tasks extremely important if difficulties arise with automatic activation, since the timer may have been set by virus software.

Be aware that in some cases the functionality of the task scheduler may be distorted by some special programs. This is especially true for software created for automatic shutdown and turning on other applications by time.

In addition, the reason for everything can be applications with functionality "Alarm", capable of independently waking up the PC and performing certain actions.

In some cases, users do not distinguish between methods for shutting down the PC and, instead of shutting down, put the equipment into sleep mode. The main problem here is precisely that in sleep the system continues to work and can be launched through the scheduler.

Always use the clause "Shutdown" in the menu "Start", not buttons on the PC case.

Now, having dealt with the side nuances, you can begin to eradicate the problem of automatic startup.

Press the keyboard shortcut "Win+R" to bring up the window "Run". Or click on "Start" right-click by selecting the appropriate context menu item.

To line "Open" enter the command taskschd.msc and click the button "OK".

Using the main navigation menu go to section "Task Scheduler (Local)".

Expand the child folder "Task Scheduler Library".

In the center of the main work area, take a close look at the existing tasks.

Having found a suspicious task, left-click on it and carefully read detailed description in the window below.

If the actions you set were not intended by you, delete the found task using the item "Delete" on the toolbar of the selected element.

Actions of this nature will require confirmation.

When searching for tasks, be especially careful, since it is the main tool for solving the problem.

Essentially, this is where the PC automatically turns on due to malfunction The task scheduler can be completed. However, it is still quite important to make a reservation that in some cases the task may be invisible or cannot be deleted.

Method 4: Removing garbage

The simplest, but often effective method, can be the simplest cleaning of the operating system from various garbage. For these purposes, you can use special programs.

Do not forget to also clean the Windows registry, as it unstable work can cause problems with PC power.

In addition to the above, do not forget to manually clean the OS using the appropriate instructions as a basis.

Method 5: Virus infection

Much has already been said about this throughout this article, but the problem of virus infection is still relevant. Precisely malicious software may cause changes to power settings in the system and BIOS.

The process of removing some viruses may require additional knowledge from you, for example, regarding Windows launch in safe mode.