> I have searched the web for WIN_TCP manuals and  have had
> no luck.

   It's probably been about 20 years since I actually cared, but in the
distant past I tended some WIN/TCP (later, PathWay) installations.  A
Web search for keywords like, say:
      Attachmate PathWay
might find more now than one for, say:
      Wollongong WIN/TCP

   On a not-totally-obsolete system, you might get some version info
from a command like:

      run twg$tcp:[pathway_admin]pathway$list_software.exe

On an older system, there may be no "TWG$TCP:[PATHWAY_ADMIN]" directory,
but there should be a "TWG$TCP:[NETDIST]".  The "hosts" file, for
example, should be "TWG$TCP:[NETDIST.ETC]HOSTS".

> I need to change the IP address etc on a system [...]

   Strictly speaking, the _system_ doesn't have an IP address, an
_interface_ has one.  The "ifconfig" command(s) which configure(s) your
interface(s) should be in "TWG$TCP:[NETDIST.MISC]STARTINET.COM".  With
any luck, the required change(s) should be pretty obvious.  ("etc" can
cover much ground, and my psychic powers are weak.)

   I have some materials lying around, probably newer than your stuff,
if you're still saying "WIN/TCP" instead of "PathWay", but much of the
fundamental stuff was pretty stable over the years/versions.  If you can
find/guess a version, then I might be able to scrape together some
things which might be of some use.  If interested, send an e-mail
message to sms at antinode.info.

> I'm not sure why you say "running system". [...]

   He said "system running [...]", not "running system".

> [...] So, shutdown all your IP services and the IP stack itself and
> then (re)configure from scratch using the new address.

   Or just say "ifconfig" with the right parameters.  It's derived from
BSD, not magic.  I'd want to test the STARTINET.COM stuff, but a loose
"ifconfig" should do the job for testing.  If "ifconfig" is not
recognized, then you might need to do something with
"TWG$TCP:[NETDIST.MISC]USERLOGIN.COM".