After connecting to the internet I am usually bombarded with messages on the screen with the title “Messenger Service” with advertisements for products. Obviously these are not real messages and are becoming annoying. How can I prevent them from appearing? This occurs even with the Internet Connection Firewall being enabled. The computer is running Windows XP Home Edition SP1.

What you are experiencing is called Messenger Spam. There is a service built into Windows called the Messenger Service, which allows network administrators to send messages which appear on the screen of computers (e.g. to warn of an impending server shutdown). However, spammers have discovered this system and broadcast messages to large ranges of IP addresses. So, you are not personally being targeted, but your IP address (i.e. your address on the internet) is within the range which the spammers are transmitting. However, this should be blocked by the Internet Connection Firewall (ICF), so I am unsure why this still occurs even with the firewall enabled. Before beginning, I suggest that you double-check that the firewall is enabled on your connection. Go to the “Start” menu > “Control Panel” and open the “Network Connections” control panel (you may need to first click the “Network and Internet Connections” category). Right-click on your internet connection and select “Properties”. In the window that appears, click the “Advanced” tab and make sure “Protect my computer or network” is enabled (ticked). Should this already be ticked, the other possibility is a firewall exception has been configured to allow this traffic. To check this, click the “Settings” button in the previous window and check the ICF configuration to see whether an exception exists for this traffic.

Assuming the messages still continue to appear, the best way to prevent this Messenger Spam from appearing is to disable the Messenger process. Go back into the Control Panel and open the “Administrative Tools” control panel (you may need to first click the “Performance and Maintenance” category). Double-click to open the “Services” window, and scroll through the list of services to find “Messenger”. Right-click on the service and select “Properties”. In the window that appears, click the “General” tab and press the “Stop” button to immediately stop the service. In the “Startup type” box, select “Disabled”. This will prevent the service from loading on startup. Click OK and close the Services window. You should no longer receive any Messenger spam.

I also suggest that you update Windows XP to Service Pack 2. This update includes a variety of improvements, including a much better Windows Firewall. You can download the Service Pack 2 update from Windows Update (windowsupdate.microsoft.com).