I quickly skimmed the Rls notes for the driver, there's just too much to ask, so take a look at http://us.download.nvidia.com/Window...ease-notes.pdf
to see if any of the known issues apply.
Guesses. Look in the Rls notes and see if these areas might affect your system.
PhysX config (CPU vs Auto Select)
Install/reinstall driver. According to the Rls notes, Control Panel, not Device Manager should be used to uninstall.
Audio messes up video - turn off audio
snapshot (PUBLISH from the Speccy file menu) and post the URL on the thread. Thanks.