Actually that wont work - try this...

code:
  

If @inwin= "1"
$os_service = ReadValue("$Compname\HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion","CSDVersion")
If $os_service = "Service Pack 3" OR $os_service = "Service Pack 2" OR $os_service = "Service Pack 1"
Run "G:\W2KSRVPK4\W2KSP4_EN.EXE -u -q -z"
EndIf
EndIf


_________________________
If at first you don't succeed, try again. Then quit. There's no use being a damn fool about it. - W.C Fields