Автор: http://www.swissdelphicenter.ch

uses
   Registry;

 procedure CDSetAutoPlay(SioNo: Boolean);
 var
   Reg: TRegistry;
 begin
   try
     Reg := TRegistry.Create;
     Reg.RootKey := HKEY_LOCAL_MACHINE;
     if Reg.KeyExists('Software\Classes\AudioCD\') then
       if Reg.OpenKey('Software\Classes\AudioCD\Shell\', False) then
         if SioNo then Reg.WriteString('', 'play')
         else
            Reg.WriteString('', '');
   finally
     Reg.Free;
   end;
 end;

 procedure TForm1.Button1Click(Sender: TObject);
 begin
   {Activate  AutoPlay}
   CDSetAutoPlay(True);
 end;

 procedure TForm1.Button2Click(Sender: TObject);
 begin
   {Deactivate Autoplay}
   CDSetAutoPlay(False);
 end;