How to email to the all mail in ASP.NET C#

public void SenEmail(string EmailAddress)
   {
       if (EmailAddress != "")
       {
           try
           {
               url = "http://www.mednob.com/new/unsubscirbe.aspx?email_id=" + EmailAddress;

               // Mail Using Domain
               MailMessage mM = new MailMessage();
               //mM.From = new MailAddress("tradelink@mednob.in", "Mednob");

               mM.From = new MailAddress("kumar@availtechnologies.net", "Mednob");

               //mM.From = new MailAddress("info@mednob.com", "Mednob");
               mM.To.Add(new MailAddress(EmailAddress));

               mM.Subject = txtSubject.Text;

               mM.Body = ConvertToHtmlFile(filename, url);


               mM.IsBodyHtml = true;


               mM.IsBodyHtml = true;
               mM.Priority = MailPriority.High;
               SmtpClient sC = new SmtpClient("webmail.markersspot.com");


               sC.Port = 25;
               // sC.Credentials = new System.Net.NetworkCredential("mail@availtechnologies.net", "Avail12345");

               sC.Credentials = new System.Net.NetworkCredential("kumar@availtechnologies.net", "seetha07");
               //sC.EnableSsl = true;

               sC.Send(mM);

           }

           catch (Exception ex)
           {

               if (con.State == ConnectionState.Closed)
               {
                   con.Open();
               }

               SqlCommand cmd1 = new SqlCommand("update  tbl_sendmail set status=0 where recipient='" + EmailAddress + "'", con);
               int a = cmd1.ExecuteNonQuery();
               if (con.State == ConnectionState.Open)
               {
                   con.Close();
               }

               wrongmail++;
               //  Response.Write(ex.ToString());
           }
       }


   }