The Microsoft Windows Messenger Service can be a useful communications tool or an annoyance, as one user posting in our Technical Q&A forums discovered. When you enable the Microsoft Windows Messenger Service, it allows anyone to send pop-up messages to your computer when you're online. Marketers are now using use the Messenger Service to display ads on user systems -- just another annoyance most of us can do without. The good news is that you have a couple of options available for disabling the service and avoiding the problems this user encountered. Make the pop-ups stop
User Mike Percival reported that after installing WinXP Professional, he started seeing unsavory ads in pop-up windows. "Whenever I connect to the internet," wrote Percival, "I get pop-up messages inviting me to view pornographic pictures on some Web site." Percival attempted to get rid of the problem by uninstalling MSN Messenger, but this had no effect. "The message," Percival added, "says it is being sent to a particular IP address, which certainly isn't mine." TechRepublic member Dave Osborne responded to Percival's query, providing information about the Messenger Service. Osborne stated that the intended purpose of the service was to allow admins to send instant messages to their users instead of using e-mail. It's a useful tool for alerting users about network outages due to maintenance or other issues. One way to eliminate the pop-up messages, Osborne stated, is to block port 135. Percival also found his own instructions for disabling the service. The caveat is that this prevents alerts from being sent to networked computers, but for home users, there's no reason not to turn it off. Because anyone can use the service to display messages or ads on your computer while you're online, the argument for blocking the port as Osborne suggested or disabling the service altogether is compelling. The service is enabled by default, so you need to take steps on your own to get rid of it if you don't want spammers to be able to display messages directly on your computer. An additional annoyance of such messages, as Osborne noted, is that they remain on top of other windows and will remain there until you close them yourself. Disabling the Messenger Service
If you don't want your computer to receive pop-up messages via the Messenger Service, you can follow these instructions to disable it on WinXP:

1. Go to Start | Control Panel | Performance and Maintenance | Administrative Tools.
2. Double-click Services.
3. In the Services panel, select Messenger as shown in Figure A.
4. Right-click and select Stop to turn off Messenger.
5. Right-click and select Properties. (You can also simply double-click Messenger).
6. From the Startup Type drop-down list, select Disabled as shown in Figure B.
7. Click OK.

On Windows NT and Windows 2000, the process for disabling Messenger is similar. Access Services in Administrative Tools and select Disable or Manual as the startup setting in the Properties. If you're receiving unwanted ads on your computer in pop-up messages, you can take these steps to turn off the service that allows your computer to receive them. However, in a corporate network environment this may not be an issue or an available option.