Everything can be changed in Ubuntu. This is what makes Ubuntu great and terrible at the same time.. I’ve bricked my Linux several times and it took hours to find the problem. It’s just easier to reset everything and start over.
If you brick you system and you are lucky to make it to the login screen after a reboot, press CTRL+ALT+F1 for a command-line. Execute the following command:
rm -rf .gnome .gnome2 .gconf .gconfd .metacity
To return to the GUI press CTRL+ALT+F7.
