Ubuntu howto: 3D support on nvidia GeForce 8xxx cards
Get the current linux-nvidia drivers from nvidia.com
Instal build-essentia, xserver-xorg-dev, linux-headers-‘insert your kernel version here sudo apt-get install build-essential xserver-xorg-dev linux-headers-2.6.x
Stop your x.org server sudo /etc/init.d/./gdm stop
In /etc/default/linux-restricted-modules-common, add nv to DISABLED_MODULES=””
Run the installation script you got from nvidia, it should take you through the installation process. When asked if you want to download a suitable Kernel from nvidia, select no.
When asked if you want to auto-configure xorg.conf select yes and reboot your machine.