I have downloaded Gnome Desktop Environments with Components in the Ubuntu 12.04 Software Manager, on reboot I still get a Unity desktop with no login menu. I have also tried:
with the same results. Do I need to do something to initialize it to get it running? I have looked around and can only find answers on how to install it, nothing to address if it doesn't start after reboot.
sudo apt-get install gnome-shell
It also doesn't show up in the Dash Home or Unity menu bar. Not sure if it's supposed to, but thought i'd mention it.