because thats how these viruses work, as mike says, this is a virus of some form. what itll do is send a message to all/random people in their address book saying stupid things like "hey just seen a great pic of you" and then a link. or as in this case, send you a file directly. once you download it, then itll do exactly the same thing again, but from your msn aswel.
on a side note, if someone knows the answer to your secret question and answers it, msn will reset your password, meaning noone can find out what the original password was.
on a side note, if someone knows the answer to your secret question and answers it, msn will reset your password, meaning noone can find out what the original password was.