uses ddeman;
 
procedure TForm1.Button1Click(Sender: TObject); 
begin 
  with TDDEClientConv.Create(Self) do begin 
   ConnectMode := ddeManual; 
   ServiceApplication := 'explorer.exe'; 
   SetLink( 'Folders', 'AppProperties'); 
   OpenLink; 
   ExecuteMacro('[FindFolder(, C:\DOWNLOAD)]', False); 
   CloseLink; 
   Free; 
  end; 
end;