Comment 11 for bug 303601

@gorillastrong2

    You can re-enable control-alt-backspace by modifying your xorg conf file to include the lines

Section “ServerFlags”
Option “DontZap” “false”
EndSection

or, according to a few blogs i found doing a search, you can run the command

dontzap –disable

I personally disagree with disabling that key combination by default, especially in regards to my laptop being unusable for the first few hours do to an issue with gfx at install... but *shrug*. once this issue with sysreq-k is resolved, i'll be a happy camper again.

 I hope that fixes your issue.