asp.net注册成功发送邮件带激活码

Question

1）注册成功发送邮件。
前台代码

收信:/asp:TextBox 主题:/asp:TextBox 内容: Width="336px">/asp:TextBox

</div> 
<table id="Table2" runat="server" border="0" cellpadding="0" cellspacing="0" visible="false"> 
        <tr> 
            <td align="center" style="width: 400px"> 
                <asp:Label ID="Label1" runat="server" ForeColor="Red" Text="恭喜您，发表成功!"></asp:Label><br /> 
                <br />
                <asp:Button ID="Button2" runat="server" Text="返回" onclick="Button2_Click" />
            </td> 
        </tr> 
    </table>   

</form>

后台代码
protected void Button1_Click(object sender, EventArgs e)
{
////设置发件人信箱,及显示名字 ,
MailAddress from = new MailAddress("邮箱");
//设置收件人信箱,及显示名字 , "0503班"
MailAddress to = new MailAddress(TextBox1.Text);
//创建一个MailMessage对象
MailMessage oMail = new MailMessage(from, to);

    oMail.Subject = TextBox2.Text;      //邮件标题        
    oMail.Body = TextBox3.Text;         //邮件内容 

    oMail.IsBodyHtml = true;            //指定邮件格式,支持HTML格式         
    oMail.BodyEncoding = System.Text.Encoding.GetEncoding("GB2312");//邮件采用的编码         
    oMail.Priority = MailPriority.High;//设置邮件的优先级为高 

    //发送邮件服务器 
    SmtpClient client = new SmtpClient();
    client.Port = 25;
    client.Host = "stmp.163.com";    //指定邮件服务器 
    client.Credentials = new NetworkCredential("邮箱", "密码");//指定服务器邮件,及密码 

    //发送 
    try
    {
        client.Send(oMail);  //发送邮件 
        Label1.Text = "恭喜你！邮件发送成功。";
    }
    catch
    {
        Label1.Text = "邮件发送失败，检查网络及信箱是否可用。";
    }

    oMail.Dispose();        //释放资源 

    TABLE1.Visible = false;
    Table2.Visible = true;  


}
protected void Button2_Click(object sender, EventArgs e)
{
    //返回，继续发送 
    Response.Redirect(Request.Url.ToString());
    TABLE1.Visible = true;
    Table2.Visible = false;  
}

怎么也发送不成功。
2）像qq空间访问量左上角的数字怎么做出来