1. From the system tray, near the system clock, click on the PC-Cillian Icon to open the Main Console window.
2. Click on Home Network & Firewall Controls followed by settings to open the Personal Firewall settings window.
3. Select the option Activate Personal Firewall, if not already checked, and click on Advanced Settings at the bottom.
4. Click on Program Control tab, and check if Windows Live Messenger is listed on the software list. If you see an entry for Windows Live Messenger, select it and click remove before proceeding. Click on Add to include the Messenger in the list
5. Enter “Windows Live Messenger” (without quotes) under Description. Select Simple and Allow option proceed to the next step.
6. Click on browse. If you are using Windows Live Messenger 8.1, browse for Windows Live Messenger by going to C:\Program Files\MSN Messenger\MSNMSGR.exe. If you are using Windows Live Messenger 8.5 or later, browse for Windows Live Messenger by going to C:\Program Files\Windows Live\MSN Messenger\MSNMSGR.exe. Click on Open to select the file.
7. Click OK to add Windows Live Messenger to the Firewall list and verify if the status is checked. Once you add Windows Live Messenger in to the list it will look like below:
8. Click on OK to complete the Wizard.