Sequential messages in WLM is not active

Hello,

Recently, i got to know that my newly installed window Live Messenger was infected by some spams.
It kept leaving unknown links to my contacts using my account while i was offline (signed out).
Therefore, i uninstall the whole package of my WLM, and then i reinstalled it back again.
On the contrary, the feature which enables sequential messages by contacts together is INACTIVE, even though i had activated the feature (by checking the setting box).
HOW CAN I SOLVE MY PROBLEM? It is very disorganized to see 10 chats windows to open individually instead of having sequential messages.

Thank you

Regards,
Juliza.