Windows 8 e avast 9 sono compatibili, quindi io la lancerei. http://www.microsoft.com/en-us/windows/compatibility/CompatCenter/ProductDetailsViewer?Name=avast%20Antivirus%20Free&vendor=AVAST%20Software&Locale=1033%2C2057%2C3081%2C4105%2C16393&ModelOrVersion=9&BreadCrumbPath=avast%202014&LastSearchTerm=avast%2B2014&Type=Software&tempOsid=Windows%208.1 ciao