On Login Button Click
==================================
           //Remeber me functionality
            if (chkRememberMe.Checked == true)
            {
                Response.Cookies["UName"].Value = txtLogin.Text;
                Response.Cookies["PWD"].Value = txtPassword.Text;
                Response.Cookies["UName"].Expires = DateTime.Now.AddMonths(2);
                Response.Cookies["PWD"].Expires = DateTime.Now.AddMonths(2);
            }
            else
            {
                Response.Cookies["UName"].Expires = DateTime.Now.AddMonths(-1);
                Response.Cookies["PWD"].Expires = DateTime.Now.AddMonths(-1);
            }


on page load
===================
//for remember me funcationality
            if (Request.Cookies["UName"] != null)
                txtLogin.Text = Request.Cookies["UName"].Value;
            if (Request.Cookies["PWD"] != null)
                txtPassword.Attributes.Add("value", Request.Cookies["PWD"].Value);
            if (Request.Cookies["UName"] != null && Request.Cookies["PWD"] != null)
                chkRememberMe.Checked = true;