I have a couple programs that use the loopback funtion on defined ports to check to see if there's a copy of the program running. I suspect if they really wanted to do it this way the program could have to statically defined ports (bad Idea in general) and it could check them both to see if there's a copy. If a message is sent it replies.

Concerning:
"(firewall blocking doesnt seem like an option!)" -- Are we speaking of every firewall or the external only firewalls.

Have you tried to block the process from sending out a message? I mean some programs such as ZoneAlarm and other internal firewalls can control the ability for a program to send any messages across any ports.
You could also try to block the port that it's sending information through after it's open.