I NEED HELP IMMEDIATELY

my comp keeps crashing, and i cant log into my acc long enough to turn off the overclocking, my moms acc work perfect but mine SUCKS and its been pissing me off HOW DO I TURN OFF THE OVERCLOCKING

second, WHY is my comp suddenly doing this its retarded

info:
ati grafix
i reset bios, uninstalled msi afterburner, deleted files i downloaded yesterday, and the dumb comp still doesnt work, my overclocking is ultra stable and i dont see why my grafix card would just quit on me now

i basically turned off voltage settings and cpu overclocking settings and after that the comp wouldnt get into my acc screen turns black or i see vertical colored lines

I NEED HELP NOW THIS IS PISSING ME OFF wasted last 2 hours trying to fix this