Sometimes GNOME gets really, really borked, so badly that you essentially need to start over. In situations like that, it's time for drastic action. Here's what you do:
If the gconfd process is running, kill it. Find the PID for gconfd with ps aux, and then kill the process using, uh, kill.
Now delete the following directories:
~/.gnome
~/.gnome2
~/.gnome2_private
~/.gconf
~/.gconfd
Restart, & you now have a virgin GNOME. This means, of course, that all the settings your had in place for GNOME apps are gone too. If that really bums you out, then back up those GNOME directories instead of nuking them, and then carefully put the right config files back into place as needed. Tedious, yes, but less of a PITA than redoing everything.
(Check out all of our posts on GNOME.)
