Easiest thig is to try the following open the webside: http://www.kaspersky.com/remoteviruschk.html

Press" browse" than go to drive c, then to “program files” folder, “alwilsoftware”, “avast4”, “data”,“Chest” and choose the file Avast moved in there(should be only one with the extention .vir) Press “open” than subbmit on the webpage.