You mean the Knoppix user has superuser priviliges? Hadn't thought of that. But the fact still remains I can't change the password of this Knoppix user, supposedly because I don't know the old password (actually it doesn't have a password). But never mind.
Anyway, after installing Feather Linux onto my harddrive I could change the root password. At least, that's what I remember. My memory isn't as good as I want it to be.
When I got tired of Feather Linux I installed SimplyMEPIS to the same partition as Feather Linux, effectively DESTROYING it
Well, I still have a copy on my USB drive.