I've tried several different driver updates for my Nvidia Geforce GTS 450 graphics card, and all fail to install. I've uninstalled it multiples times, and done a few malware scans and registry cleaners. They all don't work.
I would first run Driver Sweeper from Safe Mode (F8) and have it remove any AMD, Nvidia, and ATI graphic driver remnants it finds in the registry and elsewhere. If, after a re-boot, you still can't install a gfx driver, I would think the card may have failed. http://www.techspot.com/downloads/4266-driver-sweeper.h...
If uninstalling the graphic driver and running Driver Sweeper from Safe Mode won't let you install the latest driver, you may have to do a clean Windows install. (I presume you are trying to install the correct driver for the correct card and O/S.)
Make sure your installation of Windows is fully updated and if that doesn't work still then you could always try deleting all the Nvidia .dll files from the system32 folder and then installing the driver.
You could first make a disk image in Windows Backup. Then do the clean install. If the clean install fails to allow you to install the latest driver, you can always use the image you made previously to return your system to the way it was. The only thing you'll have lost is your time.
I have a computer exhibiting the same symptom.
Nvidia Driver Failed to install.
At first I thought it was a bad vcard but I tried swapping his 9800GT with a 560Ti I had laying arround with the same results.
I tried resetting system bios to default settings with the same end result.
I suspect the motherboard at this point but since the system is 5years old swapping that may lead to more headaches than I'm willing to go through.
I just going to build a new system and circle back on the other systems motherboard replacement later.