This bit of code should fit the bill. If not please post and I'm sure someone has the answer your looking for.

code:

---

IF @INWIN = 1
	$SRVR = ReadValue("HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ProductOptions", "ProductType")
	IF $SRVR<>"WinNT"	; System is not a Workstation so assume it is a Server
			QUIT
	ENDIF
ENDIF

---

NTDOC