What i suggest is you uninstall by manually.
1)uninstall from control panel -> programs and features-> uninstall all nvidia drivers one by one.(if it tells you to restart, do it)
2) download this program called driver sweeper( http://download.cnet.com/Driver-Sweeper/3000-2094_4-75219868.html
3)then install this ( http://www.mediafire.com/?o1kj0jki3k1k3um
4) when all drivers are uninstalled run driver sweeper and check nvidia chipset, display and physX and click analyze and clean
5) extract the ZIP from the second download and Run the program inside the folder after extraction and restart(probably do it one more time)
6) after all that mess install nvidia driver, but only install the graphic driver ONLY and check perform clean install and then restart
7) after you can install everything else( i would not download the 3d drivers)