I tried to update my Ubuntu 12.04 to 12.10. The update downloaded the needed files and then started setting up the packages. Suddenly, I saw some weird things on the screen, and then I didn't have any top or left bar. I couldn't close an app, couldn't switch between apps (alt+tab, windows key, any other shortcut didn't work). So I made a huge mistake and restarted the computer manually. When the computer booted, I chose to boot ubuntu, and then it told me that the file drive in /tmp wasn't ready to use and I should press S to skip or M to boot manually, I pressed S but nothing happened, so yet again I did another restart and this time I chose to boot recovery mode. I chose to repair packages (Something like this, I don't remember exactly), and it started going over all my packages. After it finished, I boot again and I hash a working OS (12.10) but the screen resolution wasn't good, so I logged in and again, didn't have any top or left bar, only a desktop. I managed to get into the file browser and saw that all of my files are there.
How can I repair it?