Simply use
xxxxi32.exe /q
for silent install (works on both OS).
To check which version is installed, insert
a script like this:
[CODE]
If Open(3,"c:\Program Files\Common Files\Symantec Shared\VirusDefs\Definfo.dat")=0
$x=ReadLine(3)
$x=ReadLine(3)
$NAVDefinition=SubStr($x,9,8)
Close(3)
EndIf
[\CODE]
$NAVDefinition returns the date of your current definitions...