Badly socketed ram was one of the reasons my PC started failing after being on for a while. When everything was cool it was all fine, when the case and everythi

Badly socketed ram was one of the reasons my PC started failing after being on for a while. When everything was cool it was all fine, when the case and everything heated up a bit it failed eventually. Re-seating the ram fixed it and ran for quite a time without issues. This was in the early Athlon days though.