I'm using an old computer which should be adequate for knoppix use. 500 mhz PIII, 320mb RAM, and a Matrox MGA G200 video card. This setup works fine, but on one monitor I have it won't work. This monitor, an old-school Magnavox CM2089 (says "Super VGA" on the front ), works fine in Windows with settings of 800x600 and a refresh rate of 60hz. However, when I try to boot Knoppix as follows:

knoppix screen=800x600 xvrefresh=60

I get 4 loading screens side by side, kind of overlapping.

Any help?
Thanks in advance.