Hi again,

Finally, I found out how to "fix" the problem. Just removing the battery for about half an hour helped... As far as I know does this reset parts of the flash bios.

When I started knoopix on the notebook again, it didn't happen again, so maybe I wrongly suspected knoppix to disable those keys. Nevertheless it happened at the same time as I started knoppix first, so who knows...

Anyway, the problem is fixed and I know what to do if it happens again.
And after all, knoppix is still a very fine and handy operating system

Greets from Switzerland,
Marcel