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The Fake Alert type infection mutate so rapidly that I doubt you'll find that any regular antivirus software would detect it. McAfee does have tools to combat it however.
See Fake Alert Stinger in THIS page.
Also it might be an idea to keep one or more of the tools mentioned further down under '3rd Party Tools' as extra protection for the future.
These fake alert pests are difficult to avoid, but one can go a long way to avoiding them by always keeping Windows updated - all parts of it whether used ot not - and avoid risky surfing, downloading, file-sharing etc. etc. and never click on anything you aren't absolytely sure of.