If you can start the computer then go to a terminal programme and copy the
text within single quotes (without the quotes) at the command prompt. Press
enter, type your normal user password, press enter and it should get you
back to square one. Next time you attempt the upgrade it may work better...
If however you can't start your computer at all you may need to boot from
the original Ubuntu CD, which will allow you to start some repairs, but I'm
not sure if that command string will work then - probably not. Might be
easier to just re-install, unless you have done a lot of customization.

You didn't state which version you are using. I'm no expert but I think I
heard that you can only go up one version at a time, i.e. from 8.10 to 9.04.
Ubuntu upgrades are issued twice a year in April and October. Current
version is 9.04, "Jaunty Jackalope" (possibly misspelled!), but 9.10,
"Karmic Kangaroo" will be available around the end of this month. Each one
brings some new features and inevitably a few bugs that need to get worked
out.

It is Karmic Koala, not Kangaroo. Just keeping the record straight.

My mistake, I meant updates. I am using the current version of Ubuntu. I can
still use my laptop. It just won't let me download any updates.

Same remedy, copy and paste the suggested text string at a terminal prompt
and run it. It should fix your updating issues.

Did you do what it was telling you. Please open up the terminal and type in
sudo dpkg --configure -a

Thank you for all the help. I got it fixed. I'm not a computer guru, so I'm not
use to all the computer lingo. But again Thanks for all the help. Now I just got
to figure out why Firefox screen goes gray once in awhile and why Firefox won't
link up to some sites.

Is the restricted CODECS installed?