Open up your computer and take out the ram sticks. Make sure there's no dirt and dust in the slot and that the bottom of the sticks can make good contact with the slots in the motherboard. Then, very carefully put them back in and double and even triple check to make sure they're in all the way.
Bad RAM or ram incorrectly seated in the motherboard has been known to cause weird computer problems such as random restarts, etc. Never heard of it screwing up video card drivers, though ... but it can cause restarts and freezes.