TextBox values is empty on postback :s

Hello guys,
I've trying to solve this issue since 2 days, but still not working, I tried to solve viewstate stuff in many ways but still not solved...
I had a page inside a master one the page is like
<%@ Page Title="" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="settMyAccount.aspx.cs" Inherits="Sites_Settings_settMyAccount" EnableViewState="true"%> <asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server"> </asp:Content> <asp:Content ID="Content2" ContentPlaceHolder="head" Runat="server"> <asp:Panel runat="server" id="panel1"> <asp:TextBox id="txtName" runat="server" EnableViewState="true"/><asp:Button id="btnSave& ...