I am experiencing quite major problem with Ubuntu 11.10.

Here is what happened:
I installed the closed source video driver suggested by Ubuntu (my graphics card is ATI Mobility Radeon HD 560v).
Having installed the driver I restarted the computer, and after that some parts of the Gnome UI didn't show up properly, wrong colors & unclear.
I decided to remove the driver installed as everything had worked before installation, again rebooted my computer, but this time after showing the purple boot screen, whole screen turns black and nothing happens.
I tried restart couple of times, same black screen instead of login screen.

The recovery mode of Ubuntu works so I can access terminal, only problem is that I don't know what to do.

Anyone got any ideas?