I believe this would require a service of some sort running on the box.
This could poll the computer name at regular intervals and ensure that it
hadn't changed and then react when it had. Not sure how usefull that would
be if you have to reboot when changing the name of a pc in xp.
Off the top of my head I can't recall if changing the name of a computer
requires a reboot in xp but if you had an app running on startup that
detected the computer name and then compared it to the previous name (The
app would have to store this), then you could then execute some sort of code
to respond at that point.
Sorry it isn't more helpful but I don't believe that the changing of the
computer name fires any type of event that you could handle.
