The menu bar doesn't work with any application and the unity launcher doesn't respond. In addition, I can't close a window with ALT + F4 (it works with CTRL + Q , though). But it gets weirder. If I start a session with a guest user, everything works just fine.

I've tried what they say here: Unity doesn't load, no Launcher, no Dash appears, but without success. The Compiz settings manager installs and runs fine, but I noticed that there is no checkbox next to the Unity plugin icon.

Any idea what this can be and, above all, how can it be solved? Thanks in advance.

UPDATE: As suggested by dadexix86, I tried to reset Unity with the terminal, without success. In the picture is the error message I got (sorry for the potato quality, but the screen capture isn't working, either)