Do a clean installation. Go into Windows' uninstaller, and manually remove everything with the name Nvidia. You'll have to restart at least twice (once for graphics driver and another time for sound driver, so save them for last). Then use Display Driver Uninstaller, which you can download here: http://www.guru3d.com/files_get/display_driver_uninstaller_download,9.html
Let it take you to safe mode, check the "remove C:\Nvidia folder" option, and then click the action to uninstall and restart.
Once you're normally back into Windows, go ahead and manually install the 337.88 driver again. That should clear out any driver issues. If it doesn't work, there's something else, but it definitely seems driver related, so give this a shot first. It'll take only about 10 minutes or so (depending on how fast your computer restarts).