I'm newer to overclocking and unlocking. i have a gigabyte MA790x-UD4P mobo, i unlocked my 550 but when i boot into windows some of the screen goes pixelated for a brief moment. The windows 7 splash screen also gets weird and i cant run Prime 95, it just crashes. so does this mean defective? change voltages around? sorry but like i said I'm a noob to this stuff.

help would be much appreciated =]