Ubuntu 9.04 will not boot past load screen.

I'm new to Ubuntu.
I have had continued problems with flash animations on my laptop. It had finally gotten to the point where I went into the Synaptic Package Manager and removed all macromedia packages. I went to the macromedia website and reinstalled the flash program. Soon after, Ubuntu started one of it's routine updates. I had no problems and was not asked to restart my computer so I continued using it with no problems.
I shut it off and went to bed and when I turned it on the next day, it would not boot past the load screen. Instead of going black before bringing up the login screen with it's little drumroll, it goes black and stays black with no sound.
The disk I used to install 9.04 does not have an option to rescue a broken system. When I used the help option at the install screen and looked into the option, it said that the disk did not support the ability to rescue a broken system but would be able to access the internet to find help and use the command line to manually do it.
Right now I'm online through the "Try Ubuntu without making changes to my computer" option but I don't know what command line I would use even if I knew what to do to fix the problem. I can't access my desktop to back up the files from here because I don't have permission on this version.
I have a suspicion that something I did while screwing around with the flash packages but I don't know how to solve that. Could that have been the problem? How did it happen and how do I fix it?
Is there any way to rescue my operating system and if not, is there any way for me to retrieve the files on my desktop through the trial version if I don't have permissions necessary to access the files?
Another option I have considered is creating a boot disk with the 9.10 beta and attempting to just upgrade (if it will even work) but I really need to learn how to fix these problems without starting over every time.