The check out the various things you can do to fix it, including:

 

  • Make sure any msnmsgr.exe and wlcomm.exe processes are shut down
  • Change Windows Explorer settings and delete the Messenger Contacts folder
  • Check to see if Messenger is allowed through your firewall
  • Clear the check for server certificate revocation option in Internet Explorer
  • If you're using Windows 7 or Windows Vista, run Messenger as an administrator
  • Remove the saved sign-in information in the Messenger sign-in window

Read more and get the full details for each of the above at the Messenger help Center

Get more help for Messenger

Rob