You card has the support of Windows 7 and Vista. I don't know which version of windows you have but, you can get your drivers here;http://support.asus.com/download.aspx?SLanguage=en&m=EN6600+Series&p=9&s=2&os=29&hashedid=0BvA6W0OUPgFB5SD
I have entered your info so all you have to do is click on arrow next to "choose your o/s", and choose what version you are using. Two problems you may be encountering with this card is, you may have the wrong driver, and/or you cannot install new drivers without uninstalling old versions or prior versions. The best way to handle your sitiuation now, is to get into "device manager" and uninstall all Asus software. This would include, VGA driver, "Smart Doctor" and "OSD Gamer". Then restart. Get back into your device manager and make sure all Asus software has been removed. If you have your installation CD, insert it and reinstall your drivers and "utilities",ie: Smart Doctor and OSD Gamer. You have to start with the VGA driver first in ant of your downloads, or it won't work. Remember to restart after each download sequnce is complete. If you don't have your CD or, want to upgrade your drivers and utilities(I would at this point) You can get them at the above site. You want to try and do initiall install off of CD when you can to make sure you get the bells and whistles you may not get otherwise, But it will work either way. You want to download drivers and utilities, even if you don't game, to get best results. Again, you definately want to have the VGA driver, the Smart Doctor and OSD Gamer. If you have questions let me know at "add a comment"