[SOLVED] My computer turns on by itself several seconds after shutdown or sleep. Can anyone help me?

[B0GI03]

About a month and a half ago I opened up my computer case to clean it from dust. I disconnected the cpu fan, front usb and audio jacks from motherboard, and removed the hard drive and gpu from the case in order to clean it better. I was very careful to not damage any components and i checked four times or more since that day if i put the components back in properly. After plugging the computer back in and turning it on it didn't display anything and just shut itself down after a couple of seconds as if it didn't have enough power to keep it running or as if there was some kind of a short circuit. When I turned it back on I was prompted to a bios display which is only displayed after sudden power loss and it asked me if i wanted to load optimized defaults in bios, which is what i did. After that PC started windows normally and I was able to use it as before, but when I tried to shut it down the problem from the title appeared and it remained present ever since. I turned off fast startup, wake on lan and on keyboard and mouse in windows, did a clean reinstall of Windows and even flashed BIOS, but with no luck. So I thought I should post a question here and see if anyone can help.

Thanks.

PS. I didn't find any physical damage on the components or burned capacitors etc. My computer works fine as before, it is just this problem that is present.

 

[Ralston18]

Update your post to include full system hardware specs and OS information.

Include PSU: make, model, wattage, age, condition?

Check the front panel connections. Power, Reset, Drive activity LED, etc..

Both ends. Check pins, ports, and wires.

 

[SkyNetRising]

I turned off fast startup, wake on lan and on keyboard and mouse in windows

Disable in BIOS:

wake on lan;​

wake on USB;​

wake on PCIE.​

 

[B0GI03]

Update your post to include full system hardware specs and OS information.

Include PSU: make, model, wattage, age, condition?

Check the front panel connections. Power, Reset, Drive activity LED, etc..

Both ends. Check pins, ports, and wires.

Hi, thanks for your answer
The system specs are:
PSU: Thermaltake Toughpower XT 775W, I am not sure of the age because I bought a used PC from some guy in 2018, and it has served me very well over the past 3+ years, even with CPU overclocked to 4.2GHz most of the time. But all the clocks and BIOS are now reset to default. Never had any issues with it and even now works fine.
CPU: Intel Core i7-4770k, watercooled with Cooler Master Seidon 120V
Motherboard: Gigabyte Z87X-D3H CF
GPU: Asus NVIDIA GeForce GTX 1060 6GB
RAM: PNY Electronics 16gb 1600MHz
Hard Drive: Seagate Barracuda 1TB 7200rpm
Idk if these are relevant but I'll mention them anyway:
Case: Not sure, but almost same as Thermaltake Suppressor F31
Fans: Three system fans, one connected to a fan speed controller on the case.

I disconnected and reconnected all of the front panel connectors even tried to turn the PC off with front USBs and audio disconnected from the mobo. Connections on both ends look fine. Will check the condition of the cables and connectors below the power button on the case itself.

PS. I forgot to mention that before the problem occurred when I shut down the PC the screen would turn off almost instantly, then I would wait a few seconds and then the PSU and fans would start working louder and then the computer would shut down. Now, the windows shutdown screen is present longer, and after the screen goes black, computer continues working normally and then just turns off without fans increasing their speed or PSU being louder, and then computer turns itself on.

 

[B0GI03]

Disable in BIOS:

wake on lan;​

wake on USB;​

wake on PCIE.​

Tried that but with no success...

 

[Ralston18]

The behavior suggests to me that the PSU is suspect.

Windows requires a graceful shutdown in order to do some "housecleaning" and preparations for its' next boot up. If those preparations are interrupted or corrupted in some manner - for what reason, then problems occur. Some behind the scenes update being concluded perhaps.

It is possible, depending on circumstances, that Reliability History and Event Viewer may be capturing some errors, warnings or even informational events related to the stated problems. Check both to see what may be discovered.

If the PSU is not up to par then the shutdown process will suffer.

Do you have a multi-meter and know how to use it. Or have a family member or friend who does?

FYI:

https://www.lifewire.com/how-to-manually-test-a-power-supply-with-a-multimeter-2626158

Not a full test as the PSU is not under load. However, any voltages out of spec are an indication of a problem.....

==========

Also: I noted: "But all the clocks and BIOS are now reset to default ".

If you did not do that reset then the CMOS battery may be faltering - try a new battery. Also ensure that the system's data and time stamp is correct and that any updates to time and date are being synced with an accurate and correct source for your area.

 

[B0GI03]

The behavior suggests to me that the PSU is suspect.

Windows requires a graceful shutdown in order to do some "housecleaning" and preparations for its' next boot up. If those preparations are interrupted or corrupted in some manner - for what reason, then problems occur. Some behind the scenes update being concluded perhaps.

It is possible, depending on circumstances, that Reliability History and Event Viewer may be capturing some errors, warnings or even informational events related to the stated problems. Check both to see what may be discovered.

If the PSU is not up to par then the shutdown process will suffer.

Do you have a multi-meter and know how to use it. Or have a family member or friend who does?

FYI:

https://www.lifewire.com/how-to-manually-test-a-power-supply-with-a-multimeter-2626158

Not a full test as the PSU is not under load. However, any voltages out of spec are an indication of a problem.....

==========

Also: I noted: "But all the clocks and BIOS are now reset to default ".

If you did not do that reset then the CMOS battery may be faltering - try a new battery. Also ensure that the system's data and time stamp is correct and that any updates to time and date are being synced with an accurate and correct source for your area.

I solved the issue right now by simply replacing the battery and letting the CMOS reset itself without battery for 20 minutes. The computer now works better then before regarding booting up and shutting down.

A big thank you to all of you guys who took time to read about my problem and help me. Your help is very much appreciated.

 

[EchostormFury]

Just wanted to register and thank you guys for the CMOS battery replacement recommendation -- that was absolutely it! My Z390 motherboard was just having a dying CMOS battery and would shut down only to automatically start up again and would require you to hold the power off button. I had disabled everything that I could think of even replaced the PSU 🤦 and was ready to RMA the MOBO except that it was end of life (ASRock Z390 Phantom Gaming 7) so finally I claimed an extended warranty refund from my credit card which they honored... all along the way even talking to ASRock no one recommended replacing the CMOS battery!!! GOOD JOB!