How to Install Gnome/KDE Desktop in Debian Sarge
There are two available X Window system in Debian Sarge.
Run this command in the console to install XFree86:
apt-get install xserver-xfree86 xbase-clients xfonts-base xterm
or you can run this command
To install Xorg you need to enable backports repository. Add this line in your /etc/apt/source.list
deb http://www.backports.org/debian/ sarge-backports main
apt-get install -t sarge-backports xserver-xorg xbase-clients xfonts-base xterm
Then install a Window Manager like KDE or Gnome, its up to you what to install or you can install both.
To install Gnome Desktop
However you can try also minimal version of Gnome
Same also with installing KDE
Configuring X Window System
To start your X Window System type
How to switch between kdm or gdm?
Then select which display manager to use.