急！求解！

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Login.aspx.cs" Inherits="Login" %><!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 id="Head1" runat="server">
<link href="../css/Mystyle.css" rel="stylesheet" type="text/css" />
    <title>广州中医药大学在线考试网</title>
</head>
<body style="background-color:#c0c0c0">
    <form id="form1" runat="server">
    <br />
    <br />
    <br />
    <br />
    <br />
    <br />
    <table align="center" background="../Images/Login.jpg" border="0" cellpadding="0" cellspacing="0" height="294" width="464">
    <tr>
       <td colspan="5" class="style1">
        </td>
    </tr>
    
    <tr>
                <td height="25" style="width: 180px">
                    &nbsp;</td>
                <td style="width: 69px">
                    <div align="center">
                        账 号：</div>
                </td>
                <td colspan="2" width="158" style="text-align: left">
                    <asp:TextBox ID="txtNum" runat="server" Height="25px" Width="125px" 
                        ontextchanged="txtNum_TextChanged"></asp:TextBox></td>
                <td style="text-align: left; width: 67px;">
                    <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtNum"
                        Display="Dynamic" ErrorMessage="请输入学生证号" ForeColor="DarkGray" Font-Size="10pt">*</asp:RequiredFieldValidator>&nbsp;</td>
            </tr>
            
             <tr>
                <td height="25" style="width: 180px">
                    &nbsp;</td>
                <td height="25" style="width: 69px">
                    <div align="center">
                    密 码：</div>
                </td>
                <td colspan="2" height="25" style="text-align: left">
                    <asp:TextBox ID="txtPwd" runat="server" MaxLength="12" TextMode="Password" 
                        Width="125px" Height="25px" ontextchanged="txtPwd_TextChanged"></asp:TextBox>&nbsp;</td>
                <td height="25" style="text-align: left; width: 67px;">
                    <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="txtPwd"
                        Display="Dynamic" ErrorMessage="密码不为空" ForeColor="DimGray" Font-Size="10pt">*</asp:RequiredFieldValidator>&nbsp;</td>
            </tr>
       
       <tr>
                <td height="25" style="width: 180px">
                    &nbsp;</td>
                <td height="25" style="width: 69px">
                    <div align="center">
                        身 份：</div>
                </td>
                <td colspan="2" height="25" style="text-align: left">
                    <asp:DropDownList ID="ddlstatus" runat="server">
                        <asp:ListItem Selected="True">学生</asp:ListItem>
                        <asp:ListItem>教师</asp:ListItem>
                        
                    </asp:DropDownList>&nbsp;</td>
                <td height="25" style="width: 67px">
                    &nbsp;</td>
            </tr>
            <tr>
                <td class="style2">
                    </td>
                <td class="style3">
                    <div align="center">
                    验证码：</div>
                </td>
                <td style="text-align: left" class="style4">
                    <asp:TextBox ID="txtCode" runat="server" Height="25px" Width="60px"></asp:TextBox></td>
                <td style="text-align: left" class="style5">
                    <asp:Image ID="Image1" runat="server" Width="56px" BorderColor="Gray" BorderWidth="1px" Height="17px" ImageUrl="~/Pages/Image.aspx" /></td>
                <td style="text-align: left; " class="style6">
                    <asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="txtCode"
                        Display="Dynamic" ErrorMessage="请输入验证码" ForeColor="DimGray" Font-Size="10pt">*</asp:RequiredFieldValidator>&nbsp;</td>
            </tr>
    
    <tr>
                <td colspan="5" height="25" style="text-align: center">
                    &nbsp;<asp:Button ID="btnlogin" runat="server" Text="登录" OnClick="btnlogin_Click" />
                    &nbsp;&nbsp; &nbsp;<asp:Button ID="btnconcel" runat="server" Text="取消" OnClick="btnconcel_Click" CausesValidation="False" /></td>
            </tr>
            <tr>
                <td colspan="5">
                    &nbsp;</td>
            </tr>
        </table>
   </form>
   <br />
        <br />
        <br />
        <br />
        </body>
</html>总是无法显示网页，但我试过其他代码 的都可以