Sapphire AMD Radeon HD6870

Hello, I have been having problems with my gpu not playing games. The temp is fine it runs a stable 38c and that is running 50% for the fan. When i play games tho the games either stop or i get a bluescreen. I have checked the plugs, and to see if the gpu is snug in the slot. *which it is* I took it out and put it back in, but i still have this problem. The only thing i can really think of is the drivers could not be active or something? i have the newest driver software. So my question is how do you uninstall the drivers? Anything that could help me just play some games would be awesome.

My setup is: xfx 850watt Power supply, 8gb ram, h70 liquid cooling system, Amd 3.1ghz eight core processor black edition, Sabertooth 990x motherboard, 60gb ssd, 500gb Hdd