Open up the case and check that the fans are spinning properly, and have an unobstructed path to your video card. Maybe even clean up the dust if theres enough of it. If one of the fans is dead/dying, or you got a spare spot for an intake/exaust fan, pick one up at best buy or circuit city or a similar store for about $5. If even THAT doesn't work, you may want to try underclocking it a bit just to avoid the shutdowns.
Well... I would try that out, except it's a laptop. I do know a little about the insides of a computer, except not on a laptop, plus I don't want to void the warranty. I could do it easily on a desktop though (that is, I'd ask my brother... he wont touch my laptop...)
I'll check into it though.
And, sorry I didn't make it this sunday SUNDAY
SUNDAY. I had easter EASTER
EASTER