ATI display driver keeps crashing

HI

My display driver is crashing quite regularly in games, particularly SC2 since this is the one I play the most. I only recently figured out that this was the problem when it happened on the desktop with the error message "Ati display driver has stopped responding and has recovered from an error."

My graphics card is an HD5870 running on windows 7 64bit. Catalyst version is 11.3. My pc is not overclocked and I don't think it is an overheating issue, as this often happens within the first minute of gameplay.

Any help would be greatly appreciated