Don't know if anyone can help me with this, but I'm having some huge issues with my PC since a couple of days...

The whole PC just keeps randomly crashing, like freezing for a second or two, then shutting off and rebooting. I have not a single clue what could cause this, it happens especially often while I'm in a game, but also often just when I click something in a browser or on Discord... I've also checked with a software called OpenHardwareMonitor, which monitors the temperature and the power supply of CPU and GPU among other stuff, nothing changes drastically in the last seconds before the crash.
I don't suppose anyone else has had a similar thing happening to them? :/