First, if there are any display utilities or control panels for the display card you are currently using installed in your system, uninstall them according to their instructions. 
You should also select the standard VGA display driver to ensure your system's compatibility before you continue. If you are prompted to restart your system for the changes to take effect, choose instead to restart later, then use the "Start" menu to shutdown your system normally when you are ready to remove the old display card and install the new one.