QUOTE
Yes, Windows 7 Needs Antivirus Software

Doug Caverly
Staff Writer
2009-11-04

More confirmation came yesterday that it is, quite simply, a terrible idea to leave a Windows 7 computer running without antivirus protection. Chester Wisniewski, a Senior Security Advisor at Sophos Canada, found that the operating system is vulnerable to all sorts of stuff.
Wisniewski put Windows 7 and its User Account Control tech to the test by exposing a machine to ten viruses. Without UAC active, two of the ten were stopped. UAC (at its default settings) then just kept an additional one from wreaking havoc.

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http://www.securitypronews.com/insiderrepo...usSoftware.html