If this happens on a couple of systems with different hardware, than there might really be something wrong with you cd. In my experience, at least nine out of ten systems work just fine with knoppix.

If you know a little about X configuration, you may start knoppix and wait until the cd is quiet, than get a text console with ctrl/alt/F1, type
init 2
to halt X, and edit the X config file with
cd /etc/X11
joe XF86Config-4
Once edited, try to start X using
init 5

Note that 'joe' is a text editor, you can use any other like 'vi' or 'mc'.

Pewe