edit: I was thinking you have a skin, uninstall the skin and try now
Hm this seems to be a problem your side.
Go to Control Panel>Add/Remove Programs.
Make sure Plus! is uninstalled.
Make sure MSN Messenger in uninstalled.
Restart your computer,
Once restarted, download MSN Messenger again from this link:
Official MSN 7 Website
See if it appears now, if it doesn't post again for alternative suggestions.
Then sign in and see if this is fixed.
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