Как заблокировать доступ к дисководу?

Code:

const

{©Drkb v.3}

FILE_DEVICE_FILE_SYSTEM: Integer = $00000009;

METHOD_BUFFERED: Integer = $00000000;

FILE_ANY_ACCESS: Integer = $00000000;

function CTL_CODE(DeviceType, FunctionNo, Method, Access: Integer): Integer;

begin

Result := (DeviceType shl 16) or (Access shl 14) or (FunctionNo shl 2) or (Method);

end;

procedure TForm1.Button1Click(Sender: TObject);

var

LHandle: THandle;

BytesReturned: Cardinal;

MsgBuf: PChar;

FSCTL_LOCK_VOLUME: Integer;

begin

FSCTL_LOCK_VOLUME := CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 6,

                                                 METHOD_BUFFERED, FILE_ANY_ACCESS);

LHandle := CreateFile('\\.\A:', GENERIC_READ or GENERIC_WRITE, FILE_SHARE_READ

                     or FILE_SHARE_WRITE, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL or

                     FILE_FLAG_DELETE_ON_CLOSE, 0);

if LHandle <> 0 then

begin

  if DeviceIOControl(LHandle, FSCTL_LOCK_VOLUME, nil, 0, nil, 0, BytesReturned, nil) then

    ShowMessage('Дисковод заблокирован. Нажмите ОК для разблокирования.')

  else

  begin

    if FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER or

         FORMAT_MESSAGE_FROM_SYSTEM, nil, GetLastError(), 0, @MsgBuf, 0, nil) > 0 then

    begin

      ShowMessage('Ошибка DeviceIOControl: ' + MsgBuf);

      LocalFree(Cardinal(MsgBuf));

    end

    else

      ShowMessage('Ошибка при вызове DeviceIOControl!');

  end;

  CloseHandle(LHandle);

end

else

  ShowMessage('Ошибка при вызове CreateFile!');

end;