hmm. well print screen captured it, so its most likely software. do u got a spare hdd to install an os on there to see if it still happens? when r ur freinds gonna be there?
HAHA YES!! j/k ur freinds got a spare? have you tried diff vid/ram slot combinations? well if u plan on building a new system, that one is pretty kick @$$, just get a mobo, or get a conroe(and thats comin from an amd guy). but think about it: the connecting link, the mobo...it might be starting to go, that or the procesor, can you upgrade ur bios?
it might be in your best interest to get away form the computer for a while, got any odl computer parts laying around? you could put them together or if you have a console system just use it for a while