Might be the classical issue of overheating - not so improbable as it happens while gaming. Check the cooling, clear dust from the inside...
Don't forget to clear the PSU intake - outlet. Electric components may reach high temperatures in no time, even if you're not doing something you consider heavy.
About the display driver error you suspect, you might try an older driver. Quite often they work better than the latest. If you can put your finger on the approximate date when the problem started, you could also try a Restoration Point in Windows, Control Panel\All Control Panel Items\Recovery, and choose a date before the disaster. If you do this, check what programs will be affected, because you'll probably have to re-install them...