If you need to determine the application or service that is grabbing a TCP port because of some potential conflict you may foresee with another application or service you want to install, you can do so as follows.
First, use this command to find out the PID of the offending service or application:
netstat -ano | findstr ":xxxx"
Then open Task Manager (or use the tasklist command) to match the PID to the name of the application or service.
Mitch Tulloch is a seven-time recipient of the Microsoft Most Valuable Professional (MVP) award and widely recognized expert on Windows administration, deployment and virtualization. For more tips by Mitch you can follow him on Twitter or friend him on Facebook.