Can't play ac... fucks up my pc..-.-

[yopa]

eh ok... so yesterday ac started doing some weird shit... when I opened the game... I could run around for like 20 seconds... then my fps started falling... and falling... and falling... at the end I was at 6 fps or smth, and then my screen froze. If I manages to close ac, my pc still lags for like 3 minutes, and after that it's just normal... and this happens every fuckin' time... I've tryed to reinstall it, but it was still the same...

so yeah... I would love some help. I'm usually at irc #aftershock .
tnx.