Nouveau – Open source drivers for nvidia graphic cards

1. Removing nvidia drivers

1.a)If you installed the drivers using ubuntu official repository:

apt-get –purge remove nvidia-glx-* nvidia-settings

1.b)If you used nvidia installer from nvidia website(replace VERSION with nvidia driver version!):
sh NVIDIA-Linux-x86-VERSION-pkg1.run –uninstall

2.Switch to virtual console by pressing by pressing Ctrl+Alt+F1

3. Login as root and stop gnome display manager

service gdm stop

apt-get install xserver-xorg-video-nouveau

4.Generate xorg.conf file

Xorg -configure

5.Copy the generated file to /etc/X11/

cp xorg.conf /etc/X11/

6.Edit xorg.conf

vi /etc/X11/xorg.conf

7.Search for Driver “nvidia” line in Device section and if you find it replace it with Driver “nouveau” them save and exit.

8.Restart computer.

reboot