Oh well, back to the drawing board - I really like xubuntu, but I seem
to have hit a small snag following me tweaking something to do with
the display from the settings menu (I chose a different logo)

The next reboot dumped me into "initramfs" mentioning usplash, so
after a couple of failed boot attempts (in case it was a temporary
problem) I got it into repair mode, and did an "apt-get remove
xubuntu-usplash" - which also appeared to remove xubuntu-desktop

So far, it had been a little inconvenient, but a quick "apt-get
install xubuntu-desktop" got me back to a working gui desktop again.
Great.

Problem is now i'm getting crashes in Half-Life again with the audio
enabled - which I wasn't prior to this little problem :-( - bugger.

As a sideline comment / question - does anyone know if a wubi image
can simply be copied and renamed on the host machine, to be restored /
renamed back if it does it again ?