changing video card

[Sasha Tsykin]

The best way is to load a bakup of xorg.conf and reinstall all
appropriate drivers to it. If you have installed the drivers using
manufacturer shell scripts as opposed to the apt repositories, make sure
you uninstall them (type sh <shell script name> --uninstall

If you were using the nvidia glx package from apt-get repositories got
to https://wiki.ubuntu.com/NvidiaHoaryRemoval?highlight=%28nvidia%29 for
a guide on how to remove them