A screensaver is an application that
replaces the image on a screen when the screen is not in use. The screensaver
application for the GNOME Desktop is
The following sections describe how to set preferences for the
XScreenSaver application, and how to modify the displays that
are available for the screensaver.
XScreenSaver application does not
allow you to lock your screen if you are logged in as root.
If you want to be able to lock your screen, log in as a normal user. To obtain
system administrator privileges, open a terminal window, then use the su command to log in as root.