A friend of mine had a problem with her ubuntu upgrade which left her machine unable to boot. Surprise surprise, there was no backups and loads of photos of the kids on the harddrive.
so, after trying a few things this is what worked for me.
boot ubuntu 9.10 install disk and “try ubuntu without making changes”
plugin removable drive (in this case my 200gb external)
now, while it may look like you can just copy the files over in the file manager you can’t because you do not own the files, you need to be “root”
goto Applications > Accessories > Terminal on the top menu.
in the terminal type
sudo /bin/bash
now you are root, you can fire up the file manager
at the prompt type
nautilus
A file manager window will appear that has the right permissions to copy things over to the external drive.