First, if you've never tried eVGA Precision Overclocking tool, you might want to try that. It works with most video cards, and I don't see why it wouldn't work with your Gigabyte 8800GT.
If you don't want to try that, try finding the original driver CD and see if there is an installer for GamerHUD on there?
If you don't want to try that, try finding the original driver CD and see if there is an installer for GamerHUD on there?