Lost User Name and Password after fresh install

I had took this installation into my hands as a beginner and failed to keep track of my user name and pass word due to other computer complications and not using paper.

I was given a installation disk version 9.4 if i do recall

Fully installed over winXP

Was very unsure with the installation to begin with as it was my very first ,i was able to log in until i shut down the machine and tried using it the next day.

I do not have this installation disk anymore as it was loaned to me.
The computer has been sitting for some time now and has been pretty much rendered useless seeing how i can not fix this with out some assistance. It boots up to a black screen sometimes freezes and other times it boots up to the usual ubuntu user name and password fields.

I wish to get this machine back up and running some how any advice?

Hmm...

Some Forums have rules which do not allow people to give advice about defeating the password. They reason that the computer might belong to someone else or even have been stolen.

I'm not saying that the computer does not belong to you, but if you have borrowed the installation disk once then borrow it again and reinstall. You have no material to lose.

exactly

I have the same problem except for the fact that I am solely running Ubuntu 9.10.

I have my login and password which is no longer working, I do not have the disk.

Why???? WHY!!!???? And to think that I was attempting to be proactive by updating.

Any Ideas?