If you have an advanced Video Card, you can sometimes have trouble installing the drivers. A fast and easy way to install your Video drivers is to use a program called Envy. Envy can help you with your initial installation, and any time you have to reinstall because of a Kernel update.
1- Open your favorite terminal
2- type in sudo apt-get install envyng-gtk
3- Launch EnvyNG’s GUI by selecting it in the “Applications/System Tools” menu.