Tony writes:

" I have an associate who feels his office >computer is being invaded by
a former business associate.  This computer >is a stand-alone operating
W95 and has a modem."

This is a perfect example of why computers should be shut down at night,
and not left on.  If these "invasions" are being down while the computer
is on-line, there are two things to do.  First get a good firewall.
Second, don't leave the computer logged on when it is not in use.

If someone is sitting down at the computer and "invading" that way,
change the password(s).

--Sam Smilie