i think that you should try to update drivers get a good anti-virus program because of 1: a "bad" anti-virus program can take a much amount of ram and make your game go slower...
2:maybe u caught some viruses so that can be a problem,so i recommended ess(eset smart security) i will send ya link pm me...
U should also turn off all unused program such as Internet browser skype(if u use it as communication etc.)
And btw u are running win7 so its normal that your system goes slower CUZ WIN7 USES MORE YOUR RESOURCES...
If u need something more or 2 ask pm me...
hope that i helped :D
2012-08-31 23:26:22