From Salix OS
In recent xorg releases the use of the Ctrl-Alt-Backspace key combination to zap X has been removed. You can now use the Alt-PrintScreen-k key combination, which kills the current session rather than the x server though.
If you want to get the Ctrl-Alt-Backspace key combination working, you can edit the /etc/hal/fdi/policy/10-keymap.fdi hal configuration file, find the line that refers to "input.xkb.options" and edit it like this:
<merge key="input.xkb.options" type="string">terminate:ctrl_alt_bksp</merge>
If you already have some keyboard switching options in that line just add the terminate rule next to it, using a comma to separate the two rules.