I recently switched over to Ubuntu 13.04, I used it on my Laptop it worked pretty great, then I updated it to 13.10 then further updated it to 14.04.
While upgrading to 14.04, my UI suddenly crashed - I don't know why. I installed gnome package using sudo apt-get install gnome, my UI worked but I didn't like that UI at all.
Is there any solution to restore Ubuntu's Default UI? I tried deleting ~/.config files but that didn't work either?
You need to switch desktop environment at login. Logout (or reboot) to change it.
If the above doesn't work (i.e. Unity is broken), reinstall Unity. Press Ctrl+Alt+F1 and execute:
$ sudo apt-get remove compizconfig-settings-manager compiz-fusion-plugins-extra compiz-plugins-extra
$ sudo apt-get purge compiz*
$ sudo apt-get install unity-2d ubuntu-desktop ubuntu-desktop-2d compizconfig-settings-manager xserver-xgl emerald compiz-fusion-plugins-extra git compiz-plugins-extra compiz-plugins-extra install unity
$ sudo reboot
(Source for Unity reinstall)
You can remove Gnome as:
$ sudo apt-get remove gnome-shell ubuntu-gnome-desktop
If you don't reboot, press Ctrl+Alt+F7 to go back.
sudo apt-get install ubuntu-desktopwork? – s3lph Aug 07 '14 at 14:36