If you have SP1 installed, you can just uninstall messenger from 'Add and Remove Windows Components' . This is found at the start menu > 'Set Program Access and Defaults'.

Not sure about how confined it is, but you can search for "remove MSN" and you will find several threads that have commands you can run from Start:Run to uninstall Messenger.

After that date, users will no longer be able to log in to the app and are advised to uninstall it. According to Meta, Messenger on mobile devices will not be affected. All chats and video call ...