如果不行，
請到下方網頁下載 Avast! 專用卸載工具 :
http://www.avast.com/uninstall-utility
然後重新開機到安全模式下去移除。
原廠說明 :
1.Download aswclear.exe on your desktop
2.Start Windows in Safe Mode
3.Open (execute) the uninstall utility
4.If you installed avast! in a different folder than the default, browse for it. (Note: Be careful! The content of any folder you choose will be deleted!)
5.Click REMOVE
6.Restart your computer