msn messenger=windows live messenger?

MSN Messenger is not really the same as Windows Live Messenger.

Windows Live Messenger is version 8.0+ and MSN Messenger's last version is 7.5

MSN Messenger was renamed to Windows Live Messenger as part of Microsoft's Windows Live series of online services and software.

Here you can compare the two messenger:
http://en.wikipedia.org/wiki/MSN_Messenger
http://en.wikipedia.org/wiki/Windows_Live_Messenger

Windows Live Messenger is only for Windows XP, MSN Messenger is for other versions of Windows, they work slightly different such as Windows Live Messenger contains a function with using mouse as pen writing in sending message.

55~~ msn messenger=windows live messenger

Yes

msn messenger=windows live messenger