Hi, here is a link which is also in the guide for fixing that kind of problem.
http://www.tuxgarage.com/2011/04/mis...-in-unity.html
It sounds like you my have removed ubuntu desktop. I would reset unity and compiz since you tried other methods from youtube.

Unity reset will keep running, after about three minutes just reboot by tapping the power button once and it should bring up a shut down window.
Thanks