The simplest way to gain a root gui is to log out as a normal user, then log in as root. If there are no other users that have a gui
then root will obtain a gui. It's not as convenient as it used to be.

http://www.knoppix.net/forum/viewtopic.php?t=17347

http://www.knoppix.net/forum/viewtopic.php?t=18459

should help explain.
Regards,
Mark