Desktop Pc Suddenly Shutdown And Kept Rebooting By Itself

I was watching a video file and scanning through it frame by frame dragging the cursor then suddenly
I heard the "eeennnn!" sound and computer reboot by itself with no blue screen or error messages.

It got to my MOBO flash screen and then it would just keep rebooting itself endlessly from that point on.

I did a hard reset (unplug, drain by holding power button 15 secs) and after it started up sometimes it was
ok for a couple minutes, logged back into windows, but noticed my video thumbnails weren't loading
on my desktop and then it rebooted again.

I've disconnected all external hard drives now, unplugged internet too just to make sure.
I ran hard drive scan, SMART, long, short generic, DST all passed 100%

It still keeps rebooting sporadically.

I went to view Windows Event Viewer and this is what showed up....a long list of warnings/critical/ for days it goes back. Anyone know what this means?

https://paste.pics/SN7Y0
https://paste.pics/SN7XX

 

If I'm in BIOS it still reboots on it's own.
If I'm in windows repair while trying to repair it will still reboot on it's own.
It just keeps rebooting (1 beep) and doesn't allow me to access anything.
It got worse after I used a duster to clean out some dust in case I thought it was causing a short somewhere.

 

CPU temp? Is the fan spinning? Is it water cooled? If this happens in BIOS, rules out Windows. Power supply needs testing too.

 

CPU temp, GPU temp, fans all running all within good levels. I unplugged my GPU and issue was still happening. Not water cooled. yes it reboots while in BIOS and even when it tried to "automatic starting repair/recovery" and it'll reboot in that too so you can't run bios or repair. The only thing I can think of is I need to get into safe mode but there is no way boot up safemode on this PC unless I can get into windows first.

I was able to get into windows finally and quickly set up reboot into safe mode so now im in safe mode and running RAM memory test. It has not been rebooting yet while in safe mode.

 

RAM test complete no problems with RAM. It didn't reboot in safe mode for a good 20+ minutes so I thought it was ok now but at around the 25 minute mark, the PC reboot again by itself even in safe mode. Would this indicate this is not a software issue? We've ruled out a windows issue, RAM, GPU, hard drive....the only other steps that it could be that is causing this reboot is the PSU or the Motherboard or maybe a faulty wiring somewhere causing a short? How can I test these?

 

I tried to open a software to see the voltages but now it is rebooting constantly non stop after it was fine for a few minutes.

 

Ok just to update anyone in case you have the same issue. I was able to resolve the issue it seems.
I don't know exactly which of these did it but it has worked fine now for the past few hours no more rebooting.

1. if some screw might be shorting your mobo, i put black eletrical tape on it to prevent shorting
2. I changed out the CMOS battery with a new one
3. I reseated the RAM to another slot

After doing these 3 things, the issue has disappeared.