So lately within 5 minutes to an hour based on what game I play (shorter time for crysis) (longer for something like MOH Aireborne or spore) Vista says the driver stops responding then recovers. I am pretty sure this is because normally without a game my system uses up 50-55% of my system RAM (any tips to lower that?). When the game comes on, there might be times where that memory could reach 100, therfore stopping the game from working, which makes the driver to stop responding. Once it stops, it recovers (which is what it says). So my question is, is my theory correct? If it is not, what can I do?? If it is correct is my only solution adding more RAM???

For reference I have the latest drivers installed with the last ones uninstalled, I have an 8800 GTX, a slightly OC'd quad core that has low temps, and 2 gigs of ram w/ vista ultimate.

*edit* to add to the theory, that would explain why CSS never crashes on the highest settings

I had the same problem with my 8800Ultra XXX, I thought it was something to do with corrupted video memory on the card so I got my money back and bought the 8800Ultra XT (since there were no more XXXs in stock) and then everything was fine after that, the only time it has happened on this new one is on some nvidia demos, it hasn't happened on any proper games such as crysis or stalker so far. 

I have had the same problem.. however I have a ATI 3870 X2
the solution for me was flashing the bios of my motherboard ( X48 chipset )... after I did that... the problem has stopped occurring.