Windows NT, 2000, and XP hide an hidden Internet server that is running by default. It receives and accepts, among other things, unsolicited network messages that cause pop-up dialog boxes to appear on the desktop. Internet Spammers have discovered this and are spraying pop-up Spam across the Internet. The Windows Messenger server should never have been running by default, and Microsoft has finally fixed that in Windows 2003, but users of previous Windows need to take responsibility for this themselves.

Download and run the small ShootTheMessenger.exe utility. It will display the current status of your system's Messenger Service. The button near the bottom of its window will allow you to set the service to whichever state — running or disabled — that you desire.

If, for any reason, you should ever choose to re-enable the Windows Messenger Service, simply re-run ShootTheMessenger to do so.