After a user complained of popup windows advising her to download antivirus software, I checked the system with Spybot Search & Destroy. Spybot found the following malware on the system:
I also found that the popup ad was appearing whenever Internet Explorer was opened. When Interenet Explorer was opened it would go immediately to http://aprotectservice.com/, which would result in a dubious W32.Myzor.FK@yf virus warning appearing.
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