Re: Pb with FX5900XT + 2.6.6 : nvidia drivers swpet out ...
Have you got a line like "alias char-major-195 nvidia" in /etc/modprobe.conf?
I don't see why you should have to re-install the driver. If X won't start it's probably because you haven't got the nvidia kernel module loaded. Try 'modprobe nvidia' and then 'startx'. Does that work for you?