All of a sudden RiscBSD refuses to boot. It gets as far as the beep and the
line about the VIDC20, and then freezes. The Num Lock, Caps Lock and Scroll
Lock lights all flicker. The only thing that I did prior to this was to copy
some files to the RiscBSD partition using UnixFS. However I have done this
several times before without incident. The files were copied to a special
'RiscOS' directory which I use for incoming files; they did not replace any
existing files nor have I deleted any system files. What is wrong and how do
I fix it?