Troubleshooting Windows reboots?

[dt-cam]

I connected the UPS USB cable and ran a self test, the PC stayed on, the test passed and the UPS program showed everything in good/normal status.

On 4-26-18 the computer rebooted 6-8 times (I stopped counting the entries) between 5:15pm and 8:45pm and the reboots appeared to be about 5-7 minutes apart. The last time it powered off, it didn't power back on and was off for 24 hours or so. Sometimes it boots back up on its own and other times it needs to be powered on.

At this point, I don't think it is memory related, but I will still test the memory. My gut tells me it is the motherboard.

I wish the logging was better.

Does anyone have experience with power supply testers?

 

[dt-cam]

UPDATE, I replaced the power supply, about 25 days ago, and the computer has been up and running ever since. I received a notification for windows updates which I set to remind me later/postpone/whatever the option to do it later was. This is w10, but you still get 1 or 2 changes to push updates to a later time.

Anyway, I wanted to make sure it went more than two weeks w/o a reboot before I posted the resolution.