Repair Ubuntu after unsuccesful upgrading

I was upgrading Ubuntu 11.10 to Ubuntu 12.04 and during this process I was using Google Chrome and some Nautilus windows and suddenly something came wrong (compiz or other package was updating...) X server wasn't responding. I had to restart my laptop because upgrading process wasn't going on. Since then Ubuntu doesn't stand up. After grub choise nothing shows (except blinking mouse pointer and purple background). I even can't switch to tty.

Enyone knows solution to that problem? How to repair this installation of Ubuntu. How get access to terminal (to diagnose, to check the system)?

Solution 1:

In my case, after a crash during 11.10 to 12.04 upgrade, this command completed the upgrade:

sudo apt-get -f dist-upgrade

, as suggested in https://askubuntu.com/a/122320.

About 600M of packages was downloaded and installed in the process.

Solution 2:

Try using the Ubuntu LiveCD Recovery Mode. It gives you exactly what you need for repairing the system.