uses ShellApi;

procedure TForm1.Button1Click(Sender: TObject);
var
  IconIndex: word;
  h: hIcon;
begin
  IconIndex := 0;
  h := ExtractAssociatedIcon(hInstance,
    'C:\WINDOWS\NOTEPAD.EXE', IconINdex);

  DrawIcon(Form1.Canvas.Handle, 10, 10, h);
end;