I have a 6600Gt, and i installed the nvidia drivers in ubuntu with no problem. But after a little bit, like 1 or to sesions later they seem to not work anymore. I reinstall and all is well for another sesion or two. But then, again I have to reinstall. I can tell their not working any more because cedega dosnt detect hardware acceleration, nvidia-settings do not work, and if I restart gnome X wont start, then I reisntall drivers and it works. Is there something Im missing? I followed nvidias instructions exactly I think.

do you have Nvidia support compiled into the kernel??
(not as a module)............

ummmmmm.....how do I figure that out?

EDIT: I didnt recompile my kernel, if that it. Its just the kernel that came off the ubuntu cd. How would I compile nvidia support.

i had a similar problem in debian testing.
to get it to find my card i made a script that runs 'modprobe nvidia' and put it into /etc/rc2.d. so when i boot, before my system loads x, it probes my card.
a little crude, but now i dont lose 3d acceleration after a reboot

ok here's a little more help with that:
you need to be root to do this,
go to /etc/rc2.d (never used ubuntu myself, but its basically debian so this should work for you). create a text file named S21nvidia (or S21whatever, it needs to load before gdm).
and enter this text:

#! /bin/sh
# probe that card!
modprobe nvidia

save it. make sure that it's set as executable. reboot. enjoy 3d acceleration again

Thanks, I did that, now to see if it works. One thing I didnt totaly understand is how do I set it as an executable? (sorry for the n00bish question).