How to Fix nVidia acceleration in Feisty (nVidia 8800 and legacy users)
If you want to fix this follow this procedure
sudo apt-get install build-essential
sudo apt-get install xserver-xorg-dev
sudo vi /etc/default/linux-restricted-modules*
Change the DISABLED_MODULES="" to DISABLED_MODULES="nv"
Save the file and exit.Now you need to reboot your machine.
After reboot, download the proper driver package from the nVidia website and save it somewhere where you can easily access it.
Now you need to press Ctrl-Alt-F2 to open up a console and login
Use the following command to shutdown Xorg
sudo /etc/init.d/gdm stop
Now run the following command from the location where you saved the nV file.
sudo sh NV*
Run through the installer and tell it to update your xorg.conf for you.
Reboot once again (just type reboot at the console) and you should have full nVidia acceleration.