tm = new System.Timers.Timer( 1000);
        tm.Enabled = true;
        tm.Elapsed += new System.Timers.ElapsedEventHandler(this.tm_Elapsed);

        this.Load+=new EventHandler(timer_Load);
    protected void tm_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        System.Net.WebRequest rqst = System.Net.WebRequest.Create("http://www.gatelimpianti.it/Default.aspx");
        rqst.GetResponse();
    }