is your filesystem on windows fat32 or ntfs? if ya don't know check in windows on the drive under properties or something. if its fat32 (likely if knoppix saw it) and windows is on master drive, make a directory for your windows drive like /mnt/windows (or whatever you want to call it) by doing this:
(the /mnt directory is normally where you mount things, I don't know why). then mount your drive by going
mount /dev/hda1 /mnt/windows
the hda drive is the first drive on the primary ide interface (master drive) and the #1 means the first partition. you can access the files on /mnt/windows
FYI: This is all done in the terminal, there is probably a way to do it with a graphical program, but I wouldn't know how. Also, this will only work until your restart. Perhaps somebody can show us how to add it to the startup scripts because I don't know how.
Oh yeah, if you have ntfs, it's alot harder. There really isn't full linux support, only read-only support. and you have to get a driver or something (http://linux-ntfs.sourceforge.net/
). If you have ntfs search the forums for how to do it.