okay i did that and i get this,
C:\Inetpub\wwwroot>tidy -i Default.aspx
line 1 column 1 - Warning: specified input encoding (iso-8859-1) does not match
actual input encoding (utf-8)
line 18 column 17 - Error: <asp:image> is not recognized!
line 18 column 17 - Warning: discarding unexpected <asp:image>
line 6 column 1 - Warning: <head> proprietary attribute "runat"
line 14 column 5 - Warning: <form> proprietary attribute "runat"
line 14 column 5 - Warning: <form> lacks "action" attribute
Info: Doctype given is "-//W3C//DTD XHTML 1.0 Transitional//EN"
Info: Document content looks like XHTML 1.0 Strict
4 warnings, 1 error were found!
and my Default.aspx file
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta http-equiv="expires" content="0" />
<meta http-equiv="Pragma" content="no-cache" />
<title>Untitled Page</title>
<link href="default.css" rel="stylesheet" type="text/css" />
</head>
<body>
<form id="gamerforce" runat="server">
<div id="wrap">
<div id="innerwrap">
<div id="header">
<asp:Image ID="Image1" runat="server" Width="900px" Height="197px" ImageUrl="~/images/GamerForceBanner.png" />
</div><!-- end of <div id="header"> -->
<div id="content">
</div>
</div><!-- end of <div id="innerwrap"> -->
</div><!-- end of <div id="wrap"> -->
</form>
</body>
</html>