If Gnome fails to start up with a LOT of error dialogs, look in
/var/log/messages for messages like:

messagesec 7 17:31:47 mixalot gconfd (jason-4424): Bad permissions
755 on dir /home/jason/.gconfd
messagesec 7 17:31:47 mixalot gconfd (jason-4424): Failed to get
lock for daemon, exiting: Directory /home/jason/.gconfd has a problem,
gconfd can't use it

or

Feb 25 12:07:09 Desktop01 gconfd (root-6085): starting (version
2.10.0), pid 6085 user 'root'
Feb 25 12:07:09 Desktop01 gconfd (root-6085): Bad permissions 744 on
directory /tmp/gconfd-root
Feb 25 12:07:09 Desktop01 gconfd (root-6085): Failed to get lock for
daemon, exiting: Directory /tmp/gconfd-root has a problem, gconfd can't
use it


The solution is to fix the permissions, which can be done as follows.
Go to the home directory of each of the affected users accounts, and
(where "theuser" is the user's username):

cd ~theuser
chown -R theuser:theuser .gconf .gconfd
chmod 700 -R .gconf .gconfd
find .gconf -type f -exec chmod 600 {} \;
find .gconfd -type f -exec chmod 600 {} \;
chmod 700 /tmp/gconfd-theuser

I put this into a .sh script but could not get the error checking for
user's home directory working so left it as manual commands.

PS My apologies to Jason and the Gnome gconf-list mailing list from
who I plariarised most of this information.