My computer is randomly crashing

[TopBanana78]

My computer just started to randomly crash today. I'm running windows 10. It boots up fine for the most part, sometimes it crashes on the startup. It usually crashes anywhere from 1-5 min. It's not a blue screen of death, It just shuts off instantly. I've tried swapping out the PSU, that seemed to work at first, but in the end it still crashed. I took out the CPU, cleaned it, and re-applyed the thermal paste, that worked well for about an hour or 2 until I shut it off again. Now I'm back to where i started. I used MSI afterburner to monitor the system. Everything looks normal and the CPU isn't over heating, it was at around 30 degrees. So I'm now at a loss of what to do. Any help is appreciated, thanks!

Update: It seems to work fine whenever I take the CPU out and put it back in, but once I turn it off it stops working again.

 

[MeanMachine41]

You may have instability issues TopBanana78. Due to Bios settings. Have you recently OCed your system.?
Try clearing CMOS back to default.
Try with just one DIMM in first slot and try switching modules around incase one is failing.