So, my PC started shutting down recently. I've left it doing some crypto mining(GPU only) for a while and the next day after I returned it just shut down in the middle of the game, but the keyboard and RAM sticks were still glowing. I tried turning it back on, but it didn't react until I turned off the PSU for a few minutes. After that, it also turned off multiple times even on the desktop without any load on it. All the temps seemed to be fine and the voltage values were also ok. I swapped my motherboard for a different one, but the only thing that changed was that I was able to turn it back on after it shuts down. I did some research and noticed that it also shuts down immediately after I plug in my mechanical keyboard, yet plugging in a different one doesn't seem to fix it shutting down randomly. I also tried unplugging all the HDDs except the SSD with an OS and it didn't shut down for a while, but over time it started shutting down more and more often and now it shuts down when I log into my Windows account.
Specs:
CPU: Ryzen 7-2700X
GPU: PowerColor Red Dragon RX5700 8GB
RAM: 2x8GB A-Data XPG
MoBo: Aorus X470 Ultra Gaming (and Aorus X570 Pro after I swapped it)
PSU: Cougar GEX750
Specs:
CPU: Ryzen 7-2700X
GPU: PowerColor Red Dragon RX5700 8GB
RAM: 2x8GB A-Data XPG
MoBo: Aorus X470 Ultra Gaming (and Aorus X570 Pro after I swapped it)
PSU: Cougar GEX750