That's a tough call and opinions vary. Some say you should uninstall the old drivers and then use a utility to ensure they are gone but...........
The nVidia drivers COME with an uninstaller. You run the program and it says "uninstalling old driver........" and when it finishes that it reboots and then "installing new driver......"
I use Driver Sweeper
and then install. LOL that's not what the directions say to do though.
About the automatic install....... SUPPOSEDLY to turn it off you follow the following instructions (I say supposedly because I have had it work and not work. When it didn't work I repeated the steps until it did. I reboot after doing it, but I don't think it's necessary):
To turn off automatic driver installation:
Hit Start> Control Panel> System> Advanced System Settings> Hardware (when you hit advanced system settings, the box that opens says system properties) > Windows Update Driver Settings. There you have three options. Automatic, ask, and never. Click the one you want and hit apply.
It occurs to me you should be able to right click computer and then select properties and get there as well. I'll try it after I post lol.
EDIT: nope, that didn't work (right click computer), but I KNOW there is shorter way to get to system properties.........
Edited by DeathStalker, 24 June 2009 - 11:48 AM.