Knoppix 3.3 boots part way, but when it switches to X the screen goes blank, and my Viewsonic 18" LCD monitor displays a message "Sync out of Range". This message comes from the monitor itself. Video card is Matrox G550.

The text dispayed at bootup looks like it detected the video card and monitor capabilities correctly (max 1280x1024, etc) and Knoppix boots completely but at the point it loads xwindows it goes blank and that's when the monitor displays "Synch out of Range". Ctl-Alt-Del and Enter shuts down. I've tried specifying the Xhrefresh=70 and xvrefresh=60 at bootup with same result. What now?