Hello. My friend's custom built PC is turning off by itself. I haven't turned it on for a long time until today and it seemed fine, until after 3 minutes or so, it just turned off by itself. I have tried the following: - Unplugged additional devices i.e. internal card reader, graphics card - Changed power supply - Removed 1 stick of RAM (went from 1GB to 512MB) - Formatted to Windows 7 - this was only successful once. I tried doing it several times and the installation starts up but the keyboard and mouse don't work at all. - Reformatted BIOS settings to Optimal and Fail-safe Defaults Any advice on what can actually be fixed?