what gpu and cpu do you have?
overclocking the gpu will cause the display driver to fail. usually it will recover though. but you could also be having display driver conflicts. i personally always do a manual uninstall of the old video drivers before i install a new beta or whql to make sure i get all the drivers. there are guides out there.http://www.overclock.net/t/1150443/how-to-remove-your-nvidia-gpu-drivers#post15432476http://www.overclock.net/t/988215/how-to-properly-uninstall-ati-amd-software-drivers-for-graphics-cards
please note that if you have an amd chipset/cpu that following the amd manual uninstall is not advised.
if you are having problems this can help narrow down that drivers are not causing the issue. its likely you are just overclocked too far. back down a few mhz or so. the difference between 1150mhz and 1125mhz is like 1-2 fps and isnt going to cause gaming performance to be any less or more enjoyable. hope this helps.