If the file was analyzed by the Microsoft Antimalware team via your portal submision and they responded that the file was not infected, what makes you think that you know better? It is likely that the submitted file is indeed clean, but that the malware
you encountered came via another delivery method.
Note that you have posted in the Off Topic forum for Windows Live OneCare, which clearly notes at the top of the forum that the moderators move posts into this forum and it is not for you to post questions to.
If you are in North America, you can call 866-727-2338 for help with virus and spyware infections. See
http://www.microsoft.com/protect/support/default.mspx for details. For international information, see your
local subsidiary Support site.
-steve
~ Microsoft MVP Windows Live ~ Windows Live OneCare| Live Mesh|MS Security Essentials Forums Moderator ~