I did a fresh install of ubuntu 11.10, then proceeded to install gnome-shell.
Worked wonderfully until I did a sudo apt-get upgrade...
Now logging into either GNOME or UNITY sessions, I am presented with login sounds and a blank nautilus desktop. No icons, no window manager, no panels, just my wallpaper.
Is there a way to diagnose the problem?
--UPDATE--
@Jorge: I'm able to use ALT+CTRL+DEL to bring up the logout dialog (no window manager) but PRNT SCRN does NOT respond with any screenshot dialog.
Here is an output of my .xsession-errors