hi user

 protected void Page_Load(object sender, EventArgs e)
    {

if(!IsPostback())

{
        RegisterHyperLink.NavigateUrl = "Register.aspx?ReturnUrl=" + HttpUtility.UrlEncode(Request.QueryString["ReturnUrl"]);

}
    }

Response.Redirect take round trip and redirect to you the destination page, but

Server.Transfer do not take roundtrip and do same, but the diffrence is that in

Response.Redirect your url get change but in

Server.Transfer your url remian same.