the empty quarter

UPDATE: These steps work fine for Ubuntu 9.04 (Jaunty). For more recent Ubuntu versions you should take a look at this later post which has the correct steps.

The Ctrl-Alt-Backspace key combination which restarts X is by default disabled in X version 1.6 (and hence in Ubuntu 9.04). Follow the steps below to re-enable it.

1. IMPORTANT Make a backup of your xorg.conf file. Note: messing up this file is not a good idea, so make a backup and be careful with it.
   
cd /etc/X11
sudo cp xorg.conf xorg.conf.backup
2. Open xorg.conf for editing (substitute gedit for mousepad if you are on Ubuntu)
   
sudo mousepad /etc/X11/xorg.conf
3. Add the following section at the bottom of the file:
   
Section "ServerFlags"
Option "DontZap" "no"
EndSection
4. Save the file, log out and back in. You can try the Ctrl-Alt-Backspase combination at the login window to make sure it works as expected.