Can sign into Windows Messenger but not MSNM

A friend of mine is having this weird problem.

She can sign into windows messenger (the one that’s installed by default with xp) but not msn messenger 7. says it happened after changing her internet to cable from broadband.

anyone have any clues as to what’s wrong and how to solve it?

edit: oops, forgot to update. apparently it was her AV blocking it -.-