PC wouldn't stay asleep or off, now does

[Vegasus]

After I had my Windows 10 desktop working normally for about half a year, it began to refuse to stay asleep or off. It would immediately come back on. If it helps, it's an Asus M32CD, DDR3L version with the newest BIOS. I looked for answers on the net and did the following:

Under device manager, disabled the mouse, keyboard, wifi adapter and ethernet adapter (nothing plugged in) from waking the PC. "Powercfg -devicequery wake_armed" verified those four devices could not wake the PC. I also disabled the ethernet's and wifi's "wake on pattern match" and "wake on magic packet".

Powercfg -lastwake revealed nothing.

Looked in Event Viewer, it said the causes of wakes are unknown.

The computer became unable to sleep before an update to the OS and the Asus control panel. I updated both of them out of routine.

Under Power Options: Advanced, disabled wake timers.

Upon reboot, I looked at the BIOS and didn't see anything that mentioned waking or sleeping, but I didn't look very closely either.

More command line stuff:

C:\WINDOWS\system32>powercfg -requests
EXECUTION:
[PROCESS] \Device\HarddiskVolume3\Windows\WinSxS\amd64_microsoft-windows-servicingstack_31bf3856ad364e35_10.0.10586.486_none_7640e086266ea227\TiWorker.exe
Maintenance Execution

C:\WINDOWS\system32>powercfg /waketimers
Timer set by [SERVICE] \Device\HarddiskVolume3\Windows\System32\svchost.exe (SystemEventsBroker) expires at 2:29:30 AM on 7/28/2016.
Reason: Windows will execute 'NT TASK\Microsoft\Windows\UpdateOrchestrator\Reboot' scheduled task that requested waking the computer.

After all of this, the computer would still not stay asleep or off. To turn it off last night I shut it down and in the second before it would come back on I turned off the power strip. After turning it on this morning, it would go to sleep and stay off like normal! I don't know what caused this problem, I don't know what fixed it, and I don't know if or when it will happen again. I'm using my PC normally again now, but I'm a bit anxious about future unpleasant surprises. Any ideas why this happened?

 

[nerp]

Hmm. Have you ever updated the BIOS on the board?

 

[Ketchup]

Is there anything in the Windows event logs? I have heard of computers having an error right at shutdown (as in, a fraction of a second before power off command is executed), so that the computer will reboot, because that's what it's sent to do by default in such situations.

If there's nothing there, it could point to a short somewhere in the build, maybe your power button is developing a bit of a stick, or your power supply is having issues.

If the issue went away on it's own, you probably won't know for sure until it comes back. And if it's a hardware issue, it will come back. So I just wouldn't worry about it until that time arrives.

 

[Vegasus]

Hmm. Have you ever updated the BIOS on the board?

Yes, from 501 to 602. That was about a month ago. It was working fine for a month after that.

Is there anything in the Windows event logs? I have heard of computers having an error right at shutdown (as in, a fraction of a second before power off command is executed), so that the computer will reboot, because that's what it's sent to do by default in such situations.

I'm looking through it and there's nothing right before it goes to sleep or turns off.

Separate from when it goes to sleep or wakes from sleep, there are some times when "The system has returned from a low power state." and right before that "Windows cannot store Bluetooth authentication codes (link keys) on the local adapter. Bluetooth keyboards might not work in the system BIOS during startup." But I'm using a USB keyboard and mouse.

If there's nothing there, it could point to a short somewhere in the build, maybe your power button is developing a bit of a stick, or your power supply is having issues.

I wondered about this but the feel of the power button hasn't changed. Also, since that button is set to put the computer to sleep, if it was stuck it would also cause random sleeps to occur, which haven't happened.