Try downloading the latest version of knoppix live cd at http://www.knopper.net/knoppix/index-en.html
Then burn that iso image to a cd or dvd using nero, roxio, or similar
Put the hard drive back into the computer that it came from and boot to that live CD.
When it boots completely up, there will be a knoppix folder on the desktop...click that folder and down the left side you should see a listed hdd. Probably sda1 or sda0 and then you'll see the size of your hard drive may say 80GB or however big the hard drive is. Once you know you have the correct hard drive, you just simply click on it...you don't have to change permissions with the newest version of knoppix so you should easily be able to transfer/delete any files to an external hard drive or maybe even burn them to the disk . You may have to dig for your info...I hope you know where all your docs are stored. Also, bare in mind that if you save anything on the knoppix desktop, those items will not be there if you try to reboot the knoppix cd. Best of luck, lemme know how it goes.