как закрыть доступ к cd-rom?

procedure TForm1.CD_Lock(Locked: Boolean; DriveLetter: string);
const
  IOCTL_STORAGE_MEDIA_REMOVAL = $002D4804;
var
  hDrive: THandle;
  Returned: DWORD;
  DisableEject: boolean;
begin
  hDrive := CreateFile(PChar('\\.\' + DriveLetter), GENERIC_READ,
    FILE_SHARE_READ, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
  if GetLastError <> 0 then
    MessageDlg('Error:' + IntToStr(GetLastError), mtError, [mbOK], 0);
  try
    DisableEject := Locked;
    if not DeviceIoControl(hDrive,
      IOCTL_STORAGE_MEDIA_REMOVAL, // PREVENT_MEDIA_REMOVAL,
      @DisableEject,  SizeOf(DisableEject), nil, 0, Returned, nil)
      then MessageDlg('Ошибка:' + IntToStr(GetLastError), mtError, [mbOK], 0)
  finally
    CloseHandle(hDrive)
  end;
end;