>>Is there a free tool out there that will scan the contents of the PST file and identify or repair or remove virus infected messages? I Googled, but did not find anything specifically for that. Many seem to handle incoming messages, but not ones that already exist.
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>Never tryed but You can. AVG Antivirus Free edition at http://www.grisoft.com

As far as I can tell they just scan incoming and outgoing; not already existing.