For years, Microsoft have been prohibited the launching of multiple instances of its Messenger. And since that time, there are downloads of all kinds of utilities that circumvent these limits.

The 2009 version provides the first easing Official: the ability to connect multiple locations simultaneously to a single account, office and home for example (the messages being sent to all places open).

However, it is still not possible "in theory" to launch multiple instances of Windows Live Messenger (WLM) on a single machine to enjoy your Live ID accounts, a feature often referred to as "Polygamy".

In practice, however, Microsoft has provided such a feature. A parameter hidden in registry database. Here's how to activate the "Polygamy"

- Run "Regedit" (Press [Windows] + [R], type Regedit then click OK)

- Deploy the "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Live"
For Windows Vista 64-Bit Edition users:

HKEY_LOCAL_MACHINE \ SOFTWARE \ Wow6432Node \ Microsoft \ Windows Live.
- Click the right button on the key Messenger

- Then select "New" and then "DWORD Value"

- Name the new entry "MultipleInstances"

- Double-click it and change the field given by typing: 1