Looks like I had a similar problem. I used the dvi output of the videocard then. When I used the analog output, the monitor displayed allright.
Knoppix seems to detect everything correctly as it is booting up (both 2.4 and 2.6x kernels, as well as just about every cheatcode possible), but when it goes into the graphical display.. everything is all corrupted, just looks like a bunch of graphical gibberish all over the monitor.
Any idea what I have to do in order for it to work properly? I've tried literally every cheatcode that made sense to use, from fb to setting the vsync/hsync to 60, failsafe, you name it.
*edit* Btw, this is for running LIVE off the cd, figured that would be assumed since there'd be no way for me to install it anyway seeing as I can't do anything once it's loaded.![]()
Looks like I had a similar problem. I used the dvi output of the videocard then. When I used the analog output, the monitor displayed allright.

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