If your fan is working fine on the nVidia card, the BIOS is up to date, motherboard is healthy, then follow the instruction here to completely uninstall the previous version of driver before install the updated driver. Most problem can be caused by unclean driver update with files of the wrong version mixed in.

To complete uninstall previous version driver, follow the instruction on this link:

<http://www.overclock.net/faqs/12466-info-nvidia-driver-cleaning-guide.html>

You will need to download an install a "nVidia - Nasty File Remover" to remove not just the older version of the nVidia files but the older vendors you may have before nVidia. Run this remover to remove all the older version files.

To even do a more thorough job, I suggest do a Registry clean up with Registry Mechanic, for example.

It is also a good practice to reboot before installing the newer version.

If this clean installation of driver still has problems, you may need to do some sub-optimum setting such as decrease the hardware acceleration, etc.

If it still do not work, then it is probably a hardware problem.