Just a few days ago, i was able to overclock my computer, but recently after i reformat, i can't overclock. i'm using "xtremetuner hd" to overclock a galaxy gtx 460 768mb and whenever i crank it up just by a tiny bit, my screen would go black, restore, and say "display driver stopped responding and has recovered." does anyone ever ran into this problem? if so, please help me fix it.