I don't know if this applies to your specific problem mjs01282, but I found this by doing a "Start/Help and Support" search on my computer (XP Home):
"Stop receiving pop-up ads that have the title Messenger ServiceIf advertisements open on your computer in a window titled Messenger Service, your system might not be secure. Although the name is similar, these messages—which are sometimes called "messenger spam"—are not related to Windows Messenger, MSN Messenger, or other instant messaging programs.
Disabling instant messaging programs is not necessary and will not prevent Messenger service spam. To help protect your computer, you should enable Windows Firewall (or a firewall of your choice) and also make sure that the Messenger service feature in Windows XP is disabled.
To disable the Messenger service feature in Windows XP
You must be logged on as an administrator or a member of the Administrators group in order to complete this procedure. If your computer is connected to a network, network policy settings might also prevent you from completing this procedure.
Open Services in Administrative Tools.
Double-click Messenger.
In the Services list, double-click Messenger.
In the Startup type list, click Disabled.
Click Stop, and then click OK.
Note
If your computer is part of a corporate network, talk to your system administrator before taking this action."
