Hello, I install in my Notebook Avast free antivirus, and Avast Doesn't detect Virus, the virus database is automatically update, Why avast doesn't detect virus, a friend bring me a cd of AVG free antivirus, I install AVG free antivirus and run the AVG free antivirus, the AVG free antivirus detect this 2 virus and remove them, but I want to know Why doesn't Avast Free Antivirus detect this two viruses?.