Avast Antivirus is the best security software to protect your device from threats, virus, and malware. But if in case, it stops working then your device is under danger. To fix it, first, check your subscription period for Avast. If it has been expired then get it subscribed as soon as possible. If it still fails to scan, then it might be possible that your device is already infected with malware. In that case, conduct a full malware scan of your PC and then reboot your system to start the scanning process. http://www.ukavast.co.uk/