Re: Cooling advice
random question: how old is the pc? and how long (hours) total do you think its been on? and do you live in a dus....n/m theres dust everywhere.
open up your case, (take side panel off) and peer inside, look for dust. it should be accumulated by fan's and air openings in the case. if there is a lot, get something to blow it out (like a vacuum with the hose on the exhaust port, or a can of air).
i say this because the pc sounds like its having symptoms of overheating. the heatsink can handle enough at idle, but when load hits, it cant handle it, common side-effect of dust. second, on the graphics card, i assume you have a fan on it, so ground yourself to the case, remove the card, and get all the dust off of that. (unless you can do it with it still in the case, then do that)
same goes for fans, and anywhere else thre is dust. just get it all out.
if you are still having problems, then i guess a reinstall is in order. (on the otherhand, prebuild heatsinks are crap, so you might want to upgrade that.)
what is the make/model of your pc?