xserver - How do I fix "Your system is running in low-graphics mode"?

Possible Duplicate:
How to fix “The system is running in low-graphics mode” error?

I installed 12.04 LTS (upgraded from 11.10) but When I start my computer it shows

Your system is running in low-graphics mode, Your screen, graphics card, and input device settings could not be detected correctly. You will need to configure these yourself.

And then shows a dialog to choose, what I want to do, but this one doesn't work correctly.

So I can access only terminal but I don't know how to set this stuff or how to start GUI. Because I'm terminal kiddies :-)