Shoutbox

try this:

   1.      Exit MSN Messenger completely.
   2.      Click Start, the Run, type regedit and click OK.
   3.      Navigate to:
MyComputer\HKEY_CURRENT_USER\Software\Microsoft\MSNMessenger
   4.      Click (don't double-click) the MSNMessenger key. It should simply highlight the name.
   5.      Go to the Edit menu and click Delete. Click Yes to confirm the operation.
   6.      Install MSN Messenger 6 and sign in!