This may help.
How to find open ports on a computer
You can use PULIST from the Windows Resource Kit to find which process
is using a specified port. For example, pulist |find /i "4125" may display
.... www.howtonetworking.com/command/openport1.htm
Hi
You have to be specific and explain what do you need the port for?
If it is an Hardware port look at the the computer's hardware manual.
If it is a network port. There are about 64000 ports most of them are
available, the choice is usually done according to the application that
needs the port.
Jack (MS, MVP-Networking)