Fix graphics issues in Ubuntu

ubuntu-graphics-fix-1204

http://askubuntu.com/questions/41681/blank-screen-after-installing-nvidia-restricted-driver

Remove everything to do with the Nvidia proprietary drivers.
sudo nvidia-settings --uninstall
sudo apt-get remove --purge nvidia*

Start from scratch.
sudo apt-get remove --purge xserver-xorg-video-nouveau xserver-xorg-video-nv

Reinstall all the things!
sudo apt-get install nvidia-common
sudo apt-get install xserver-xorg-video-nouveau
sudo apt-get install --reinstall libgl1-mesa-glx libgl1-mesa-dri xserver-xorg-core

Reconfigure the X server.
sudo dpkg-reconfigure xserver-xorg