When I try to open the program I get the error message,
C:\Program Files\Alwil Software\Avast4\ashAvast.exe is not a valid Win32 application. It seemed to load fine and after I restarted my system it did a complete files check before the welcome screen. What is wrong and how can I fix it?
Go to the ADD/REMOVE PROGRAMS control panel, doubleclick on avast! and then select REPAIR. It should help.