The Messenger Service was originally designed for use by system administrators to notify Windows users about their networks. It has been used maliciously distribute a virus to users over the Internet.
To disable the Messenger Service in Windows XP
Click Start and then click Control Panel
Click Performance and Maintenance. (If you do not see the Performance and Maintenance icon, you may be using Classic View. 3. You can skip to step 3 below, but you must double-click Administrative Tools.)
Click Administrative Tools
Double-click Services
Right-click Messenger -> Properties
In the Startup type list, choose Disabled
Click Stop, and then click OK