In Redhat 5.9, when gdm starts up from runlevel 5, it completely ignores keyboard input, which makes it rather difficult to type in a username and password. Attempting to switch to another virtual console (i.e., ctrl-alt-f1) does nothing except bring up another gdm (screen flashes black for a moment as if dropping to console, and then gdm immediately comes up again). There's no way to get to the console and switch back to runlevel 3, so the user is left with no option but to reboot. This problem also apparently happens with kdm, too. The keyboard works fine at all other points: at the console, in X, etc. Just not with kdm or gdm.