Comment 11 for bug 433928

I may write it incomplete. While booting could you edit (e) the grub menu item for ubuntu to show sth like this:

        linux /boot/vmlinuz-2.6.28-13-generic root=UUID=b02e1934-12dd-418a rw

Careful there's no quiet,splash or vga command after rw. If you could manage to open up at least a command-line interface could you please check if you can connect to internet to update your files.

If there's dbus error while you're trying this, you can try so start dbus , hal ,network-manager with start command.

sudo start dbus
sudo start hal
sudo start network-manager

and finally try starting gdm. If you got any errors doing these please write that down here.