I don't understand how the site can "not be existing" anymore.. but what I'd suggest you to do is to try to update to the latest msn messenger ( 7.0 ) if you really cannot install it as you say, then how about trying version 5.0 or l8er?
here's a site with all the msn messenger versions :
http://www.oldversion.com/program.php?n=msnm
now, a last thing would be to maybe use the Web Based version of msn on
http://webmessenger.msn.com
hope this helps you out
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