changed

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Security.Cryptography;
using System.ComponentModel;
using System.Text;

public partial class Login : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        loginFail.Visible = false;
        emailFail.Visible = false;
    }

    protected void loginButton_Click(object sender, System.EventArgs e)
    {
        string IndvConnString = System.Configuration.ConfigurationManager.ConnectionStrings["SQLAzureConnection"].ConnectionString;
        SqlConnection IndvSignCon = new SqlConnection(IndvConnString);

        IndvSignCon.Open();

        SqlCommand cmd;
        SqlDataReader rdr;

        Type checking = this.GetType();
        string checklogin = "SELECT * FROM Customer";
        cmd = new SqlCommand(checklogin, IndvSignCon);
        rdr = cmd.ExecuteReader();


        while (rdr.Read() == true)
        {
            if (email_textbox.Text == "" || password_textbox.Text == "")
            {
                return;
            }
            else
            {

                if (email_textbox.Text == (string)rdr["cEmail"])
                {
                    string usernameSTR = email_textbox.Text;

                    string getUserIDStr = System.Configuration.ConfigurationManager.ConnectionStrings["SQLAzureConnection"].ConnectionString;

                    SqlConnection getUserIDCon = new SqlConnection(getUserIDStr);

                    SqlCommand getUserIdCMD;

                    string userIdSTR = "SELECT cID FROM Customer WHERE cEmail = @UserName";

                    getUserIdCMD = new SqlCommand(userIdSTR, getUserIDCon);

                    getUserIdCMD.Parameters.AddWithValue("@UserName", SqlDbType.VarChar).Value = usernameSTR;

                    getUserIDCon.Open();

                    SqlDataReader getUserIdRDR = getUserIdCMD.ExecuteReader();

                    while (getUserIdRDR.Read() == true)
                    {
                        int userIDInt = (int)getUserIdRDR["cID"];

                        string MatchHashStr = System.Configuration.ConfigurationManager.ConnectionStrings["SQLAzureConnection"].ConnectionString;

                        SqlConnection MatchHashCON = new SqlConnection(MatchHashStr);

                        SqlCommand MatchHashCMD;

                        //Compare HashValue

                        string CompareHashStr = null;

                        byte[] compareSource;

                        byte[] compareHash;

                        CompareHashStr = password_textbox.Text;

                        compareSource = ASCIIEncoding.ASCII.GetBytes(CompareHashStr);

                        compareHash = new MD5CryptoServiceProvider().ComputeHash(compareSource);



                        string MatchHashSQLStr = "SELECT cEmail FROM Customer WHERE cID = @CustomerID AND cPassword = @CompareHash";

                        MatchHashCMD = new SqlCommand(MatchHashSQLStr, MatchHashCON);

                        MatchHashCMD.Parameters.AddWithValue("@CustomerID", SqlDbType.Int).Value = userIDInt;
                        MatchHashCMD.Parameters.Add("@CompareHash", SqlDbType.VarBinary, 16).Value = compareHash;

                        MatchHashCON.Open();

                        SqlDataReader MatchHashRDR = MatchHashCMD.ExecuteReader();

                        while (MatchHashRDR.Read() == true)
                        {
                            string exstUserNameStr = (string)rdr["cEmail"].ToString() ;

                            if (exstUserNameStr == usernameSTR)
                            {
                                Session["sFlag"] = "T"; // sFlag = "T" means user has logged in
                                Session["sName"] = rdr["cFullName"];
                                Session["sAddress"] = rdr["cAddress"];
                                Session["sEmail"] = rdr["cEmail"];
                                Session["sMobile"] = rdr["cHp"];
                                Session["sCompany"] = rdr["cCompanyName"];
                                Session["sCustomerID"] = rdr["cID"].ToString(); //ToString() Convert Integer to String
                                string strCustomerId = (string)Session["sCustomerID"];
                                DataRoutines DRObject = new DataRoutines();
                                DRObject.CreateRecs(strCustomerId);


                                IndvSignCon.Close();
                                getUserIDCon.Close();
                                MatchHashCON.Close();
                                Response.Redirect("MyAccount.aspx");
                            }
                            else
                            {
                                Session["sFlag"] = "F";
                                Session["sName"] = "";
                                Session["sCustomerID"] = "";

                                loginFail.Visible = true;
                            }
                        }
                        MatchHashCON.Close();

                    }

                    getUserIDCon.Close();

                }
                else
                {

                    emailFail.Visible = true;
                }
            }
        }
        IndvSignCon.Close();
    }

}