<A target="_blank" href="http://krebsonsecurity.com/2010/04/fake-anti-virus-peddlers-outmaneuvering-legitimate-av/">Malware writers are overwhelming people, with misleading pop-ups and videos</A>, luring them into installing malware disguised as anti-virus software. If your real anti-virus software is even a few days out of date, you're more likely to be attacked.