Enable Multiple Instances of Windows Live Messenger for Multi Logins

http://www.mydigitallife.info/enable-multiple-instances-of-windows-live-messenger-for-multi-logins/

1. Run Registry Editor (regedit).
2. Navigate to the following registry key:
KEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Live\Messenge

For 64-bit (x64) OS, go to following registry branch instead:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows Live\Messenger

3. In the right pane, right click on any blank space, select New on context menu, and then click on DWORD (32-bit) Value.
4. Name the new registry value entry as MultipleInstances.
5. Modify the MultipleInstances and set its value data as 1.