1. Launch the Windows Firewall.
1.a. Click on START and RUN to open the RUN Window.
1.b. In the RUN window type in CONTROL FIREWALL.CPL and click OK to open the Windows Firewall settings window.
2. Click on the Exceptions tab to view the list of programs that have been added to Windows Firewall,
3. Remove all MSN Messenger entries from the Windows Firewall Programs and Services list. Note: this is to ensure that the latest version that you are currently running is the one registered with Windows Firewall. To remove earlier versions, select each entry for MSN Messenger or msnmsgr and click the Delete button.
4. Add MSN Messenger through the Windows XP firewall.
4.a. Click on Add Program below the Programs and Services list.
4.b. Select MSN Messenger on the Programs list of the Add a Program window, and then click on OK.
4.c. If you cannot find MSN Messenger, click on Browse. Locate the MSN Messenger executable file by going to C:\Program Files\MSN Messenger\ and choosing msnmsgr.exe. Messenger will now appear in the Add a Program window. Click on OK to close the window.
4.d. After adding MSN Messenger to the Programs list, the firewall Programs list will look like this:
5. Click here to get more information on Windows Firewall.