Thread moved because it isn't a Plus! related problem.
You could try to do the following:
- Close Messenger completely
(right click on the icon next to the clock and choose Exit)
- Go to Start > Run and type %appdata%\Microsoft\MSN Messenger
- Press OK
- Find out what number matches your account by using this little program
- Delete that folder
Note: you will lose all your display pictures, custom emoticons and backgrounds by doing this. Reboot your computer; it should work now.
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