this is where I got into beryl instalations instructions
Running the nVidia installation package
For the installation of the nVidia drivers to continue, X.org must be shut down. Note that after executing the following command, it is not possible to return to a graphical interface until X.org is restarted.
One way to shutdown the X.org server is by stopping GDM. To do so, execute
sudo /etc/init.d/gdm stop
Now, actually running the installer is possible. Run...