Stab in the dark here but because I recently came across this exact problem.

Have you ever had Zone Alarm installed on that machine and uninstalled it?

I guess any other uninstalled firewalls "Might" do it but ZA can leave the
firewall service behind and running when uninstalled improperly, and this is
exactly what it does.

Right now I can't think of another answer, sorry, will think about it later.

Charlie

"Mark" <markxyz59@cox.net> wrote in message
news:43b9604e.16896875@news.east.cox.net...
> Hi Charlie,
>
> I don't really want to mention the program, or the port, as it might
> give away info on how to compromise my system. Suffice it to say that
> on computer PC#1 (XP Home SP2) I run the sever and then do netstat
> -ano and I see the server listening to the port. When I run it on PC#2
> (Also XP Home SP2), it starts normally, but does not show up as
> listening to the port.
>
> Note that this server uses localhost, so there's no external network
> connection involved. It basically looks at 127.0.0.1:<port X>.
>
> What windows XP system files control the ports? Does Winsock do more
> than just dial-up? I'm thinking I can copy a few system files from
> PC#1 to PC#2 if something's corrupted.
>
> M.
>
> On Sun, 1 Jan 2006 12:30:34 -0600, "Charlie Tame" <charlie@tames.net>
> wrote:
>
>>It's unlikely that any sort of virus would stop a port opening unless it
>>happened to be trying to use the same port (in which case it really isn't
>>a
>>virus but a Trojan). What security software is running and are you 100%
>>sure
>>all firewalls are behaving as they should?
>>
>>Can you mention specifically what you are trying to run and what network
>>layout you have, presumably there's a router is there? Are you seeing any
>>kind of error messages?
>>
>>Charlie
>>
>>"Mark" <markxyz59@cox.net> wrote in message
>>news:43b6fb91.26750109@news.east.cox.net...
>>> Hi,
>>>
>>> I have a Game Server that opens port X and allows a localhost client
>>> to connect. This Server works on a machine with XP Media Center SP2,
>>> and my wife's XP Home Edition SP2, but not on my kid's XP Home Edition
>>> SP2.
>>>
>>> I've confirmed (using netstat -ano) that the Server successfully opens
>>> port X (TCP) on the machines it works on. But, on the kid's PC, it
>>> fails to open a port.
>>>
>>> I'm guessing the kid's PC had some kind of virus on it, but now it's
>>> clean. What can I do to get port X working again.
>>>
>>> Note: the kid's PC connects to the internet and all else works well.
>>> Also, I have the firewalls and antivirus stuff OFF when I test, though
>>> on the other machines, the firewalls and antivirus don't affect the
>>> Server and it works fine.
>>>
>>> Any ideas, besides upgrading to XP Pro?
>>>
>>
>>
>