The search feature here works and will get you...
Driver Stopped Responding And Recovered!
Display Driver problem
HD5850 "Display driver stopped responding"
Display driver stopped responding
Nvidia - Display Driver nvlddmkm stopped responding
And as I posted before....
There are many theories on the causes as well as fixes. While one fix might work for some, others find they don't work at all.
This issue affects both Nvidia and ATI video cards, in both Vista and Windows 7
Some find that replacing the card fixes the problem. When I first encountered this issue that's what I had to do as I found the card to be faulty.
And before I get beat up - This is NOT saying there isn't a problem elsewhere, it's just saying what some, including myself have done to fix the problem. Again, for me, it turned out my card was faulty.
However, I personally think there's a problem in the way Vista and Windows 7 handles info from the video cards which may be too sensitive thus triggers the Display stopped responding warning prematurely even on a slight hiccup from the card.
Overclocked and/or overheated video cards are particularly prone to this issue but even properly functioning cards can trigger the warning.
My two cents.