I had this problem for a while. RAM problems can cause it, so I swapped ram, which didn’t fix it. Temps were good, so it wasn’t over heating. I put a new PSU in and the problem went away for about a year. (From 600w cooler master to a 850w EVGA G2) I decided to dig deeper and learned that the problem can also be caused from bad GPU drivers…well I constantly experience driver problems. I’ve never been able to update my [AMD] GPU drivers without it running into a error. WIN and AMD where fighting to be the one who installs it. I used DDU, as well as followed JayzTwoCents instructions on preventing windows from installing GPU drivers. Win still tries to install them tho, so I got a program from Microsoft (shared to a windows help forum) that can hide certain available updates. So far, fingers crossed, fixing the drivers seems to have solved the PC shutting down/restarting problem for me. It makes me think my other PSU might’ve been fine too.