U posted the question a little wrongly .. U should say msn will not install n' not that msn won't run.
Anywayz
It's not any kind of special protectionsoftware or nothing like that ...
It's just that ur user account doesn't have permissions to install anything on the machine ...
Sorry to tell ya ..but no there's no way to install msn ..without admin rights....
But then if u somehow get some admin or someone else to install it for u .. n' then it doesn't sign in ..then u can use an HTTP Tunnel like hopster
Also instead of trying to install msn on ur machine .. u can use it on the web itself .. This is damn useful when u can't install msn on a local machine
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