while i was updationg ubuntu 9.04, the battery of my laptop run out of
energy and my laptop shutdown during the updating
now i just can't have access to ubuntu!
if it can help, alt+F2 still working.
staycoolmec


If you can get a prompt then type: sudo apt-get install -f
Then you can do: sudo apt-get update
and: sudo apt-get upgrade

This should complete the installation process and allow you to get back in after
a re-boot.

The first one fixes any broken packages. The second one updates apt for the
latest package lists and the last one upgrades packages than have newer
versions.