You might try "knoppix vga=normal" at the boot prompt.
See other cheatcodes: http://www.knoppix.nl/3.6/knoppix-cheatcodes.txt
and good luck.
When I boot Knoppix v3.7 EN I have an error like:
Fatal Error: Unable to reserve frame buffer memory...
Is there another frame buffer..
or something like that.
After the error occures sometimes I hear the logging sound but everything is in black no consol no graphics nothing.
The second case is that I hear nothing and I see the gray background and the x-cursor but that is all.
You might try "knoppix vga=normal" at the boot prompt.
See other cheatcodes: http://www.knoppix.nl/3.6/knoppix-cheatcodes.txt
and good luck.

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