Hey, welcome to the forum.
- Have you tried uninstalling Plus! to see if the problem still occurs?
- Could you tell me which operating system you're using?
- Are you using an administrator account?
- Do you have any other Messenger related applications, such as SweetIM and/or SmileyCentral? (If yes, see here)
- What other applications do you have running (such as security apps which may interfere with Messenger)?
Apologies for so many questions, but there's lots of different problems it could be, so getting specific details is essential to finding the source of the problem.
Chris