Find your kernel version by issuing this command in a terminal:
Then install the Linux headers which correspond with this kernel version.
Download the latest NVIDIA driver for your graphics card from the NVIDIA web site. Store in /tmp.
Run the install package using:
sudo sh /tmp/nvidia_installer.run
(Then name of your downloaded package might be different)
Go to a terminal again. issue:
sudo /etc/init.d/gdm stop
sudo /etc/init.d/gdm start
It is supposed to work now. Substitute kdm for gdm if you use KDE.