change password

i have done below code for change user password but their is no result and not working kindly help me to resolve this query....

i want to change password when user try to change password then first current password should be verify from the table...

my code is below....where i made mistake kindly help me ....

SqlConnection con = new SqlConnection(sqlCon);
con.Open();
string sqlSelect = "SELECT * FROM LOGIN_MASTER WHERE PASSWORD='"+ txtoldPassword.Text +"'";
SqlCommand cmd = new SqlCommand(sqlSelect, con);
//SqlDataAdapter sda = new SqlDataAdapter(cmd);
SqlDataReader sdr = cmd.ExecuteReader();
if (sdr.HasRows)
{
    //while (sdr.Read())
    //{
        if (sdr["PASSWORD"].ToString() == txtoldPassword.Text)
        {
            SqlConnection con2 = new SqlConnection(sqlCon);
            con2.Open();
            string updatePass = "UPDATE LOGIN_MASTER SET PASSWORD='" + txtconfPassword.Text + "' WHERE USERID='" + Session["uname"].ToString() + '";
            SqlCommand cmd2 = new SqlCommand(updatePass, con);
            SqlDataAdapter sda2 = new SqlDataAdapter(cmd2);
            cmd2.ExecuteNonQuery();
            lblmessage.Visible = true;
            lblmessage.Text = "Password change successfully...";
            con2.Close();
            Session.RemoveAll();
            Session.Abandon();
            Response.Redirect("~/Sign_In");
            Session.Clear();
        }
        else
        {
            lblmessage.Visible = true;
            lblmessage.Text = "Old Password Not Matched, Re-enter currect old password";
            txtoldPassword.Focus();
        }
        sdr.Close();
        con.Close();
    }
}