function Proc(Wnd: HWnd; Memo: TMemo): boolean; stdcall; 
var 
  Buffer: array[0..max_path - 1] of char; 
begin 
  GetWindowText(Wnd, Buffer, 100); 
  if StrLen(Buffer) <> 0 then 
    Memo.Lines.add(StrPas(Buffer)); 
  Result := True; 
end; 
 
procedure TForm1.Button1Click(Sender: TObject); 
begin 
  Memo1.clear; 
  Memo1.scrollbars := ssBoth; 
  Memo1.Lines.beginupdate; 
  EnumWindows(@Proc, Integer(Memo1)); 
  Memo1.Lines.endupdate; 
end;