Авторизация на сайте

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("http://securecheats.net/login2/");
        void Post_g()
        {
            string Login =       "qazwar";
            string Password = "123456";
            string authString = "user=" + Login + "&passwrd=" + Password + "&submit=&cookielength=-1";                                                      
            UTF8Encoding encodind = new UTF8Encoding();
            byte[] buffer = encodind.GetBytes(authString);
            request.Method = "POST";
            request.Host = "securecheats.net";
            request.KeepAlive = true;
            request.ContentLength = buffer.Length;
            request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; rv:18.0) Gecko/20100101 Firefox/18.0";
            request.Headers.Add(HttpRequestHeader.AcceptLanguage, "ru-RU,ru;q=0.8,en-US;q=0.5,en;q=0.3");
            request.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip, deflate");
            request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;
            CookieContainer cookie = new CookieContainer();
            request.CookieContainer = cookie;
            request.ContentType = "application/x-www-form-urlencoded";
 
            Stream newStream = request.GetRequestStream();
            newStream.Write(buffer, 0, authString.Length);
            newStream.Close();
        }

Post_g();
 
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            CookieCollection cookies = new CookieCollection();
            cookies = response.Cookies;
            Encoding responseEncoding = Encoding.GetEncoding(response.CharacterSet);
            StreamReader strReader = new StreamReader(response.GetResponseStream(), responseEncoding);
            string htmlText = strReader.ReadToEnd();
response.Close();
 
            richTextBox1.Text = htmlText;

</h3></div>
            <div class="adk_7"></div>
            <div class="my_blocks" id="adk_block_9" >
                            Hey, <strong>qazwar</strong>, you have <a href="http://securecheats.net/pm/">0 messages</a>, 0 are new.<div class="text_align_center"><br /><a href="http://securecheats.net/logout/?f1989ecfd29=3ee100c2ede39896a46732ed020d6f94">Logout</a></div>
                
                            </div>
                            </div>
                    </div>

string reg="<a href=\"http://securecheats.net/logout/?f1989ecfd29=3ee100c2ede39896a46732ed020d6f94\">Logout</a>";
if (reg.indexOf("Logout")!=-1){MessageBox.Show("Autorizacion Good");}
else{MessageBox.Show("Autorizacion Error");}