Windows Messenger Service: The Windows Messenger Service is an unfortunately named component of Windows that cannot be uninstalled. It has nothing to do with instant Messaging, really, and can almost always be safely turned off. Here's how:
Right Click on My Computer
Click on Manage
Expand the Services & Applications node
Click on Services
Scroll down to find, and then double click on Messenger
In the resulting dialog box, set the Startup Type to Disabled.
Click on Stop to stop the service immediately.