Re-installing Messenger definitely won't get rid of the virus. What you need to do is run a good virusscanner and let it scan your entire system, make sure every virus it find will be removed.
After you are sure the virus is removed (the virusscanner doesn't find any threats anymore), change your Messenger password and secret question on
https://account.live.com/.
As for retrieving your email, look in the mail trashcan and other folders. If they are not there it's most likely gone forever if you don''t have a backup.
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