Проверить URL

function GetUrl(const url: string): Boolean;
var
HTTP: TIdHTTP;
begin
  Result := False;
  HTTP:=TIdHTTP.create;
  HTTP.ConnectTimeout:=60000;
  HTTP.ReadTimeOut:=60000;
  HTTP.HandleRedirects:=false;
  try
    HTTP.Get(url);
    if HTTP.ResponseCode = 200 then
      Result := True;
  except
    Result := False;
  end;
  FreeAndNil(HTTP);
end;
//применение
   while not GetUrl('http://www.***************.com') do begin
   LabelB2.Caption:='Сервер не доступен!';
   Application.ProcessMessages;
   Sleep(50);
   end;