What happened to my MSN?

My MSN 7.5 is okok till yesterday. And today When I on my laptop hor, it changes to Window Live Messenger. Can anyone till me what happened?

Did somebody use your laptop yesterday?

Did you click on the alert that MSN Messenger has a new version and will install for you?

My sister used my laptop yesterday. There is no alert that MSN Messenger has a new version because I just installed it the day before.

Then that settles it. Your sis probably installed the new version.

Ya.. I just called her and ask.. She say she install the Window Live Messenager 8.0 Evil or Very Mad