public string send(string url, string par)
    {
        String secondStepForm3 = par;
        HttpWebRequest request3 = (HttpWebRequest)WebRequest.Create(url);
        request3.UserAgent = "Opera/9.80";
        request3.Method = "POST";
        request3.ContentType = "application/x-www-form-urlencoded";
        byte[] EncodedPostParams3 = Encoding.Default.GetBytes(secondStepForm3);
        request3.ContentLength = EncodedPostParams3.Length;
        request3.GetRequestStream().Write(EncodedPostParams3, 0, EncodedPostParams3.Length);
        request3.GetRequestStream().Close();
        HttpWebResponse response = (HttpWebResponse)request3.GetResponse();
        string lol = new StreamReader(response.GetResponseStream(), Encoding.UTF8).ReadToEnd();
        return lol;
    }

string Auth = send("http://www.studymode.com/login.php","username=assemdos&password=qwerty");