Response.Write(System.Web.HttpContext.Current.Session.SessionID);Response.Write("<br />");               
Response.Cookies.Add(new System.Web.HttpCookie("ASP.NET_SessionId", ""));                
Response.Cookies["ASP.NET_SessionId"].Expires = System.DateTime.Now.AddDays(0);
System.Web.HttpContext.Current.Session.Abandon();
Response.Write(Response.Cookies["ASP.NET_SessionId"].Value);
Response.Write("<br />");                
Response.Write(System.Web.HttpContext.Current.Session.SessionID);Response.Write("<br />");