Note: Windows XP and Windows Vista always has TCP/IP installed, so you don't need to check this if you are running Windows XP and Vista.

To check if your computer has TCP/IP installed you can do the following:

1. Select the Windows Start button, then the Settings menu, and then the Control Panel from the Settings menu.
2. Double click on the Network icon.
3. Look in the top list box in the Configuration tab.
4. If you do not see an entry that starts with TCP/IP then you have not installed TCP/IP. You can install it using the How to add TCP/IP instructions.

If TCP/IP is installed on your computer and you still cannot see anybody in your Office Messenger "To:" list, then it might be the case that you have a personal firewall installed on your computer. You need to make sure that the firewall has been configured so that the following ports are available for Office Messenger to use:

UDP port number (streamed port):        2230

TCP/IP port number (datagram port):    2240