Nvidia doesn't do people that way they pack the driver for all their Gefor6 through to gtx 590 in one package so it is easy. The only difference is support and for newer cards needs a newer package. Just go on their site and download the latest package and give it a try.
1. Uninstall all old GFX drivers.
2. Reboot ... if you get a prompt to install drivers cause it found new hardware, do a Nancy Regan and "Just say no".
3. Use a registry editor to remove all nVidia GFX related items in registry.
4. Turn off machine and install new card.
5. Boot ....say "no" again if prompted.
6. Install latest driver.