I have that code which does the job

oFS = CREATEOBJECT("Scripting.FileSystemObject")
cDrive = SUBSTR(SYS(16,1),1,2) &&"C:"
If oFS.DriveExists(cDrive)
  oDrv = oFS.Drives.Item(cDrive)
  lnvol=oDrv.SerialNumber
  lnvolhex=substr(transform(lnvol,"@0"),3,4)+right(transform(lnvol,"@0"),4)
  ?lnvolhex
ENDIF

What would be an alternative if WSH is not installed on a given machine?