Microsoft’s John Weisenfeld shared a little trick that enable you to sign into Messenger with several WLIDs. The trick involves registry editing, so please follow these steps very carefully:
- Start regedit (admin)
- Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Live
- Right click Messenger and create a new DWORD called MultipleInstances
- Right click the newly added registry key and choose Modify
- Set the Value data to 1
- Close regedit
Now you can launch Windows Live Messenger as many times as you want, and sign in with as many WLIDs you want, on one computer. Just don’t try to sign in with the same WLID more than once on one computer or it will throw error 80071392 at you!