desktop environments - Ubuntu 13.04 no menu bar

I have lenovo thinkpad T520. Just updated to 13.04. I can see desktop icons, but no menu. I can start terminal, but I cannot close windows, move them or resize them. Also, Alt+Tab does not work. I have tried a few things, such as
menu bar and launcher missing in ubuntu 13.04

but no luck. Please help, I've waisted a whole day on this.

Thanks!