While upgrading the system was suddenly shut down. When restarted I could not login.

[somangili]

I was upgrading to 7.10 from 7.04 in my office computer. It took a lot of time and when I was out someone shut down my computer. When I restarted I could not login. When I changed the session to gnome fail safe I could login. But I could not connect to the internet and could not start the update manager. Can anyone help.