uses
Registry;

procedure CDSetAutoPlay(SioNo: Boolean);
var
Reg: TRegistry;
begin
try
Reg := TRegistry.Create;
Reg.RootKey := HKEY_LOCAL_MACHINE;
if Reg.KeyExists('SoftwareClassesAudioCD') then
if Reg.OpenKey('SoftwareClassesAudioCDShell', 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;