[2020] Regular crashing the whole PC

If your PC is crashing, windows will create a log in the event viewer for you to look at. Open the event viewer and look for a critical error around the time of your crash and restart. It should have a code amongst other things that will tell you why windows shut down to protect itself.

In my experience, these kinds of issues are nearly always a heat problem. Your cpu is probably overheating.

Just to add to Smoker’s comment above, I’d recommend having a look at this article: https://support.fatshark.se/hc/en-us/articles/360038965013--PC-PC-crashing-losing-responsiveness-or-Blue-Screening-BSOD-