I don't think that a knoppix-CD is the right thing to backup or repair your data.
Try to get a CD booting to Windows PE, there was a CD in one of the CT-magazines (germany).
I have had such a problem some month ago and was able to copy all my data to an usb-drive. But i must be true and say that i had got a recovery-cd with repair-programs like ontrack and so on, and this rescued almost anything. My prob was the installation of ubuntu which caused the windows-disk to be unusable. But i did never get the system to be repairable by windows, i had to format and install windows again, but lost no data.