WIth Knoppix 3.3, worked correctly with simple <cr> at the boot: prompt.

With 3.4, a simple <cr> resulted in "the blank screen of nothing".

Thanks to another post on Compaq Presarios, I found that

knoppix acpi=off noscsi

allowed the system to boot properly into the knoppix account running X.

The builtin wireless card doesn't work (31-Jul-2004), but I haven't tried very hard. Waiting for another day.