Well, I wrote a little program that monitors the ports on my computer and keeps a record of attempted accesses along with the data transmitted. I am sure there are many commercial (and freeware) programs that do the same thing (and much more) but I haven't really investigated this - I guess I am kinda a do-it-yourself sort of guy when it comes to computers.
One thing you can do to make sure you don't have any unwanted services running on any of your ports (i.e. potential security holes) is to go to https://www.grc.com/x/ne.dll?bh0bkyd2 and have it scan your machine.
Running Win98se. Can I close port 139, and if so, how?