I am using gnome-shell on Ubuntu 11.10. After I installed some of the extensions, whenever it logs in; it would not show the userbar (the one with the clock etc). I tried doing the following:
How to remove and reinstall GNOME 3?
But it just doesn't work. Obviously uninstalling will work, but I would like to be able to use the gnome-shell, and not completely remove it - as soon as I install it again; the same problem persists. The userbar does not show up, I just get the background image, and no GUI at all.