HI, I have intel core 2 duo with nvidia geforce 8800 gt,, my PC was working fine with windows 7 ultimate 64 bit.. game were running perfectly, when I formatted my PC and reinstalled windows 7 ultimate 64 bit then my PC started lagging, I tried all new drivers for nvidia but still lagging,, when I plug out my graphics card from PC then it does not lag and runs smoothly,, I don't know what's the problem with my graphics card,, I also tried vry old drivers of nvidia, on that drivers my nvidia worked fine and PC did not lag, but few new games require new drivers and with new drivers my PC lags,, I have another nvidia card,, 8400 gs, it was also working on the other window but now PC also lags with this one... ohh one thing I forgot to mention,, on nvidia geforce 8800 gt. I changed settings in nvidia control pannel, I changed colour depth from 32 bit to 16 bit,, my PC stopped lagging but when I play any game, the game lags,, I don't now what's the problem,, please help,, thanks