Folks, can anyone help me identify the stupid port that enables messaging through the "net send -IP address here-" command? And tell me how to close it?

It seems to be the port 135 but have a look on this (http://www.chebucto.ns.ca/~rakerman/trojan-port-table.html) .

You could turn off the messenger service if it is just the messages that are bothering you.

You could also run a firewall or a Port blocker, either will allow you to set which ports you don't want to allow access to/through.

(With some firewalls you can even ban the program/command)