procedure TForm1.Button1Click(Sender: TObject);
var
  fs: TFileStream;
  s: string;
begin
   fs := TFileStream.Create( 'Имя файла', fmOpenRead or fmShareDenyNone );
   SetLength( s, fs.Size );
   fs.Read( s[1], Length( s ) );
   fs.Free;
   Label1.Caption := s;
end;

procedure TForm1.DisplayHint(Sender: TObject);
begin
   Label1.caption := GetLongHint( Application.Hint );
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
   Application.OnHint := DisplayHint;
end;