ER HOW-TO: End screen spam through MESSENGER

Windows 2000, Windows NT, and Windows XP all include the Messenger Service originally configured for corporate network messages. Knowing that it's enabled by default, crafty spammers figured out that this presented them an opportunity to send SPAM through it. THAT's a MAJOR FLAW.

Here's how to disable it:

Right-click My Computer and click Manage.
Click Services and Applications.
Click Services.
Scroll down to Messenger and right-click the entry.
Stop the Service.
Choose Disable as the Startup Type.
Click OK.