Its a tracking cookie. i believe its java related. just turn off java and in firefox turn on dont follow me and the tracking sites use in cookies and such wont be allowed access. Avast is garbage also . Your much better off using Malwarebytes or Spy Bot Search and Destroy. Never trust Mcafee or Nortons as they catch nothing.Same with Avast! which is horrible and uses a ton of resources with tons of false alarms and missed detections. Run Malwarebytes after you run Avast! and you ll likely find more bugs. Also good to have are CCleaner and ATF Cleaner which are all free. Make sure when you come to this site you use multiple free proxies like hidemyass.com so your ip is not directly linked to the site then to your home computer. the more proxies used in a row the better.