you don't even have to remove the old drivers (from experience)...
just make sure you can log in w/o your mouse... i.e. force CTRL-ALT-DEL login, 2000 style. if you log in w/o mouse and reboot, you should be good to go in only a couple of reboots (switching from my FIC VA503+ to my Gigabyte GA7VRX required only one reboot)