To prevent anybody on the Internet from generate pop-up messages on your PC, you can immobilize the Messenger service. You can enable the service easily afterward if you decide to use it.

Windows XP Home

Follow the given steps to Disable Windows Messenger:

a. Click Start >>Settings >>Control Panel

b. Click Performance and Maintenance >>Click Administrative Tools

c. Double click Services Scroll >>down and highlight "Messenger"

d. Right-click the highlighted line and select Properties >>Click the STOP button.

e. choose Disable or Manual in the Startup Type scroll bar >>Click OK