I have a PC which is randomly shutting off (the hard way, like someone pulled the plug). It's no heat problem, because this can happen after 2 minutes of operation or after 4 hours and I checked the temperature. It's also no problem of the operation system, because it will also do that while in BIOS. If it happens once, you can be sure that it will happen within the next hour another two or three times, and then it works again for over a week or even longer.

Possible causes I've thought about so far are:

• Voltage Fluctuation
• Loose contact (already replugged all cables within the PC, no luck)
• Faulty PSU

Maybe someone has more ideas to this?

P.s.: I don't have the hardware specs with me right now, I'll post them as soon as I get them.