Quote Originally Posted by JAlvoeiro
I did try the failsafe testdvd command once again, but this time I did wait longer
and the knoppix did come up in failsafe mode.
If it's passing the test then I do have doubt that there is anything wrong with the DVD.

Quote Originally Posted by JAlvoeiro
But the problem is still that if I use the knoppix testdvd command the pc just hang
up completly. I did wait for about 90 minutes. I think this is enough time for the
system to work.
Yes, I agree. But look at what failsafe does and what a normal boot does; failsafe bypasses a lot of the hardware detection that can go wrong on some systems. It's a way to try to get Knoppix up, but without some things that may be rather important, such as a network connection. I suspect (I did all along) that Knoppix is having a problem with your hardware somewhere and may need a "cheat code" to get past some issue. While you are waiting for thet replacement DVD (or perhaps after it fails too) you can try reading the cheat code section of the wiki again and looking for codes to try. Unfortunately, this is not always simple; I had problems on my notebook back with Knoppix 3.4 (Knoppix 3.1 and 3.2 booted without problems) and months later I found that I needed not one but rather two cheat codes used together to boot the system. Using either one by itself the system would still hang and fail to boot.

You may also want to step through the boot process using expert mode. It will ask questions at each part of the boot process. Where it hangs may tell you something, and you can try booting again, answering all the questions the same up to that point but answering the failing question differently.