Determining if a port is available
1

Locate the Services file and open it with a text editor such as Notepad. The path to this file will vary depending on the version of Windows in use.

Windows XP:
         C:\windows\system32\drivers\etc\services
           
 Windows NT and Windows 2000:
         C:\winnt\system32\drivers\etc\services
Windows 9x and  Windows ME:
         C:\windows\services
2

Right-click on the Services file and choose Open With from the contextual menu.

3 In the Open With dialog box, choose a text editing application such as Notepad to open this file.
4 Review the list of port numbers that are in use to determine which ports are available.