no virus or malware that infiltrate MSN Messenger (this is an instant messaging program produced by Microsoft)
The most common way of infection is that you send a picture, file, or an attachment, via file transfer, and to be opened or executed, this, will infect the computer (PC).
Will run as processes suspects in Task Manager
It is best not to open the file unless you are sure the sender (and not a virus) you sent the executable
Infected after what will do is forwarded to all contacts who are online