Apart from loading the kernel and starting the system, a number of services such as cron , gdm, cups etc are started at this time. If you have installed additional services on your system, such as a web server, they will also be started at boot. Sometimes, you may want to either stop or temporarily disable these services, and Ubuntu provides a number of ways to do this, both graphically and through the command line.
Services Administration Tool
The graphical tool to start/stop services is localted at
You can also start it by typing the following command from a terminal.
$ sudo services-admin
Press unlock and enter your password. The screen will change to the one given below.
To disable a service, just deselect its checkbox and click Close. In Jaunty, this application supports changing only whether a service starts at boot. If you want to manually start, stop, or restart a service at a given point of time during your system usage, you need to refer to the command-line method.