Use this function to determine the serial number of the CDROM.  
Will only return a result if there is a CDROM in the drive.    uses MMSystem, MPlayer;    function CDSerialNumber(CD: Char): string;
{ func to return the serial number on the CD.  Works on audio & data CDs. }
var
  mp : TMediaPlayer;
  msp : TMCI_INFO_PARMS; 
  MediaString : array[0..255] of char;
  ret : longint;
begin
  mp := TMediaPlayer.Create(nil);
  try
    mp.Visible := false;
    mp.Parent := Application.MainForm;
    mp.Shareable := true;
    mp.DeviceType := dtCDAudio;
    mp.FileName := CD   ':';
    mp.Open; 
    Application.ProcessMessages;
    FillChar(MediaString, sizeof(MediaString), #0);
    FillChar(msp, sizeof(msp), #0);
    msp.lpstrReturn := @MediaString;
    msp.dwRetSize := 255;
    ret := mciSendCommand(Mp.DeviceId,
                          MCI_INFO,
                          MCI_INFO_MEDIA_IDENTITY,
                          longint(@msp));
    if Ret <> 0 then
      begin
        MciGetErrorString(ret, @MediaString, sizeof(MediaString));
        Result := StrPas(MediaString);
      end
    else 
      Result := StrPas(MediaString);
    mp.Close; 
    Application.ProcessMessages;
  finally
    mp.free; 
  end;
end;    使用方法：
 Edit1.Text :=CDSerialNumber('D'); //假設D為光碟機所在位置