Hi,
man, you're really great. It worked fine. So I did it:

1. Booting Knoppix
2. Right-click on the hda1 partition icon on the desktop
3. selected "actions..." from the menu that pops up
4. click on the entry "Change read/write mode" or so.

Now I can work with Knoppix almost like with Windows.
Thanks again, Greetings from Germany
s-m-n