Gnome won't fire up for non root users

[Martin Hanneghan]

All of a sudden, Gnome has stopped working if I attempt to login to
FC3 test 3 as a non-root user. Even if I create a new user, they can't
login. I've tried deleting all the .gnome related files and
directories for the user but to no avail.

Any suggestions how to fix this (or why it happened?) - I'm guessing
some permissions have got corrupted somewhere since root still has a
Gnome graphical desktop.

Non-graphical login works fine (e.g. failsafe term or logging into a
console window outside of X). XFCE works fine but KDE is bombing out
too saying the session lasted less than 10 seconds...

Regards
Martin