I would download drivers 275.33 however you can, either in safe mode or normal; if you can. I would then boot into safe mode. Then uninstall Nvidia Physx driver, then the Nvidia Graphics Drivers. Then go to your main hard drive, probably C:, then Nvidia>Display Driver. Delete that Display Driver Folder.
 
Then reboot into the normal desktop and run the 275.33 you just downloaded. Do a custom install once it starts, then make sure you deselect everything except the Display Driver and Physx. Also make sure the check box is checked for "perform a clean install". After that, reboot, and see how it works.