If by mistake you remove the Printing menu in Start menu of Ubuntu (System > Administration > Printing menu in Ubuntu Dapper), then to install / bring back it run: sudo apt-get install gnome-cups-manager
To install MPlayer on Ubuntu Dapper, add following lines to /etc/apt/sources.list file: deb http://archive.ubuntu.com/ubuntu dapper multiverse deb-src http://archive.ubuntu.com/ubuntu dapper multiverse After saving the file, run these two commands on a console: sudo apt-get update sudo apt-get install mplayer
When I ran "sudo apt-get install gnome-core", I lost all the menu items in System>Administration. To get back the basic menu items like "Time and Date" or "Users and Groups", just run following command: "sudo apt-get install gnome-system-tools"