Thanks for the replys.
What I'm getting is the knoppix blue screen, then

loading vmlinuz........
loading miniroot.gz........

then a black screen

when I tried vga=normal I got the above, plus:

Ready.
Uncompressing Linux....OK, booting the kernel

then everything froze (blue screen and above writing stayed on) no response to any keyboard input. Which is a step further than I have been before, but not far enough!!

I also tried xserver=XF86_SVGA xvrefresh=60 vga=normal

with the same results

monitor is a Mag innovision model dx15fe.

any more suggestions?