procedure TForm2.Button1Click(Sender: TObject); 
var 
  Flash: FLASHWINFO; 
begin 
  FillChar(Flash, SizeOf(Flash), 0); 
  Flash.cbSize := SizeOf(Flash); 
  Flash.hwnd := Handle; 
  Flash.uCount := 10; 
  Flash.dwTimeOut := 300; 
  Flash.dwFlags := FLASHW_ALL; 
  FlashWindowEx(Flash); 
end;