pre6 upgrade: X starts, but only the cursor

[sean darcy]

After a yum update since from pre 6 X won't start up completely. 
Actually X starts - I get the x mouse cursor, and Xorg.0.log looks fine. 
But that's it: just the x mouse cursor against a black background.

Tried switchdesk kde ( usually use gnome ) and xfce. Same result.

I downgrade metacity to metacity-2.16.0-4.fc6.x86_64. Again same result.

I've updated to rawhide x86-64 as of today.

I'd file in bugzilla, but I don't even know what to file against.

Any ideas on how to figure this one out would be appreciated.

sean