my PS used to just crash and freeze completley at any random time, then i got a few things done and i have no problems since. my PC is 100% custom i bought every piece seperate. to start, my 1st problem was a infinite loop error with my geforce(PC froze and restarted at random times).. so i bought an ati still the problem continued. then my HD failed, twice. so then i learned power supplies can cause HD failures, so i bought a brand new 450 watt PS with a brand new HD. still have freezing and problems. one day fooling around in bios.. i saw my idle cpu temp was like 175F(O_O). so i bought a kickass cooling system and some thermal grease, (arctic silver 5) and now i have 0 problems everything is all fixed. i would say the new power supply and definitley the cooling system fixed my problems. also if u have an ATI card, i would disable the VPU recover thing cuz its new and still all messed up..
i was going to just reply in amarok's thread but i saw multiple people complaining about problems so i just started a new thread =/.
this is what did it for me so im not saying it will fix anything for u.. but heating is a problem and definitley causes crashes.
hope this helped someone