I have installed Ubuntu 14.04. It worked for approx. 2 days. But today when I turned it on launcher & Menu bar was absent & ctrl+alt+t was also not working. I tried "sudo service lightdm restart" it didn't worked. Please help me.. and launcher is present in guest session but not in Admin login..
If above command doesnot work try this(it saved me a week ago): `Ctrl+Alt+F1´
sudo service lightdm stop
sudo service lightdm start
Further look here: 14.04 LTS No Dash / Launcher after update through Software Updater