If ur X server is down, u should have deleted all ur corrupted x files,
let's say ur gnome crashed, what u need to do is go to ur account's home directory:
cd /home/john (John is the user let say)
The all u need to do is delete all the directories as mentioned below:
.gconf
.gconfd
.gnome
.gnome_private
.gnome2
.gnome2_private
.gnome-deesktop
i.e.
[root@diskless richard]rm -fr .gconf
And restart ur box (just to make sure). And it will recreate all the deleted directories.
And u r done
If i doesn't work?
Well, don't login using Gnome, use KDE instead. Until now i use KDE i havent gimme a headache. It's pretty good to use.