When every I update NVidia drivers or if I have to roll them back this is what I do for a clean install.
During the installation you will be asked to select the Installation Option.
IT IS IMPORTANT that you select Custom. You will then see a list of options to install. They will all be checked.
At the bottom of the list there will be a check box that says Perform A Clean Installation. CHECK THAT BOX. Then let the driver install.
I have never had any problems doing it this way.
I used to have the toughest time installing a new nVidia driver. But sometime last year nVidia cleaned up their installer process. I've been using the Express option for a while now without any issues for my games (personal system) or with Adobe software (edit system).
Hell, I just updated to 314.07 today and didn't even need to reboot.
I second Dave's suggestion about using the "custom" install and would also add that you unclick any components you do not need such as the 3D vision components and PhysX system Software.
Thanks for you comment Jim Simon; I'll stop checking the "clean installation" box and see how things work out.
I have only had to install a different nVidia driver once, after Windows Update decided that I needed a newer driver, and installed a version that caused problems with my GTX285 card (I think it was a 306.something version, but didn't make a note)
I removed the "new" driver via Control Panel, restarted so Windows went into the generic driver, then installed 310.90 which works fine
I also found out how to remove an update from Windows Update http://technet.microsoft.com/en-us/magazine/ff382716.aspx