Common left panel (launcher) is disable too.
I think i should reset settings. How can i do it? PS i can start terminal.
From your keyboard CTRL+ALT+T will give you terminal and type there as ccsm
.That will launch compiz settings manager .there you can re-enable your Unity.
If CTRL+ALT+T is not working (doesn't open a Terminal), try this:
Right click & add a folder, click on the folder to open the File Manager, go to /usr/share/applications, from there you can start CompizConfig & enable the Unity plugin.
Source (Thanks @Raja)