uses
      ActiveX,
      ComObj;

    var
      FSWbemLocator : OLEVariant;
      FWMIService   : OLEVariant;

    function  GetWMIstring(const WMIClass, WMIProperty:string): string;
    const
      wbemFlagForwardOnly = $00000020;
    var
      FWbemObjectSet: OLEVariant;
      FWbemObject   : OLEVariant;
      oEnum         : IEnumvariant;
      iValue        : LongWord;
    begin;
      Result:='';
      FWbemObjectSet:= FWMIService.ExecQuery(Format('Select %s from %s',[WMIProperty, WMIClass]),'WQL',wbemFlagForwardOnly);
      oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
      if oEnum.Next(1, FWbemObject, iValue) = 0 then

  if not VarIsNull(FWbemObject.Properties_.Item(WMIProperty).Value) then

     Result:=FWbemObject.Properties_.Item(WMIProperty).Value;

    FWbemObject:=Unassigned;
    end;

    procedure TForm4.Button1Click(Sender: TObject);
    var
      X:string;
      Y:string;
    begin
      FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
      FWMIService   := FSWbemLocator.ConnectServer('localhost', 'root\CIMV2', '', '');

      X:=GetWMIstring('Win32_BIOS','SerialNumber');
      Y:=GetWMIstring('Win32_PhysicalMedia','SerialNumber');

      ShowMessage(X+';'+Y);
    end;