With the Msn version update, old versions have become inoperable. For those who have upgraded to Windows Live Messenger 2009, they can’t log in single-login, because either they couldn’t find the right patch or a crack hasn’t been written for some versions yet. We will explain the single sign-on method for Windows Live Messenger 2009.
Start / Run, Type “Regedit” and Click OK
HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows LiveMessenger find the directory
Select “New / DWORD” on the right. Change the name of the new DWORD record to “Multipleinstances” and set the following value to 1 too. Good luck with multiple MSN 2009…