I think he has already restored to BIOS factory defaults.

At first his flatmate was helping him do this because his flatmate is a massive computer nerd. I think he fucked it up in the first place by overclocking it too high, but he then turned down the settings. After that it seemed okay but a lot of his programs were crashing, so now it's on default settings, but the blue screen happens more often when he plays Total War Shogun.