Win 11 reboots itself

[esebm]

Hi, I'm running win 11 (23H2) and for about a week now my desktop reboots itself 3-5 times a day out of the blue.
What's going on here?
Also, it seems that MS Edge runs constantly in the background. Can that be turned off?
I'd really appreciate any advice.

 

[esebm]

Guys, I'm back. The issue was gone for several months, no shutdowns at all. Now it's back with a vengeance.
And, no, the power connector does not seem to be the issue.
I have the PC open on a desk, power supply opened, wiggled all cables/connectors, no reaction.
I'm planning to apply a hair dryer to to target-heating various areas in order to, maybe, trigger a shutdown.

 

[esebm]

Hi Guys,
Heated the open PC and the open power supply with a blow dryer and every time when the PS is heated, the PC turns off after about 5 seconds. So, it stands to reason that the PS is the culprit. The current one is an EVGA 500BR. I did do quite a bit of research online and I keep seeing conflicting reviews about EVGA, Corsair and a bunch of other brands. Which brand/model to buy? Can you guys give me some advice based on your respective experience? Just a "normal" office PC, no gaming involved.