Possible Duplicate:
Unity doesn't load, no Launcher, no Dash appears
I recently tried to update my desktop to 12.04- I was actually still using 9.10, so I've gone through the update process several times already, and this was the last one. I restarted, and it went to the log-in screen just fine, but when I log in, all I get is a the background image. There are no bars, no dock- I can right-click and do some settings menu stuff, but that is all. How can I fix, if possible?
As mentioned by Fossfreedom,
your question is similar to this one.
And its answer may be the answer you are expecting.
To confirm that the reason of the problem is the Unity installation,
before trying the solution of the similar question, you can try opening your session without Unity => with a GNOME Classic (no effect):
either when you chose your session
or if you are using an auto login:
/etc/lightdm/lightdm.conf (I personally edit using vi)greeter-session=gnome-fallbacksudo reboot