type

TForm1 = class(TForm)

private

{Private declarations}

   procedure WMSysCommand(var Msg: TWMSysCommand);

     message WM_SYSCOMMAND;

public

{Public declarations}

end;


procedure TForm1.WMSysCommand;

begin

if (Msg.CmdType = SC_MINIMIZE)  then

   MessageBeep(0)

else

   inherited;

end;