Send 1000s of Emails Without Timeout

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class Progress : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //first check to see if any exceptions occurred
        if (Session["ProcessRunning"] != "0")
        {
            Response.Write("<META HTTP-EQUIV=Refresh CONTENT=\"3; URL=\"\"> ");
            return;
        }
        else
        {
            Page.RegisterStartupScript("newWindow", "<script> window.opener.location.href= 'Default.aspx?id=1'; setTimeout('close()', '500');</script>");
        }
    }
}