Vertical scroll bar is disabled while viewing page in browser!!!

Here is the css.

body
{
overflow:visible ;
height :101%;
}
#masterTable
{
width: 100%;
position: fixed;
top: -5px;
right: 0px;
left: -2px;
}
masterTable Id is being used on Master Page for Master contents.
Here is the css for content area
#contentTable
{
margin: 0px auto 0px auto;
border-style: none;
border-width: 10px;
right: 0px;
left: 0px;
border-spacing: 0px;
width: 100%;
text-align: center;
border-collapse: collapse;
overflow: visible;

}
keep in mind that i am using visual studio 2008
Here is my content page's code implemented by a master page.

<%@ Page Language="C#" MasterPageFile="~/MasterPage/Main.Master" AutoEventWireup="true" CodeBehind="WebForm8.aspx.cs" Inherits="MasterPage.WebForm8" Title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<table id="contentTable">
<tr>
<td>
<div id="SubContainer">

</div>
</td>
</tr>
</table>

and css of SubContainer is here
#SubContainer
{
border-style: none;
border-width: -20px;
text-align: left;
width: 980px;
margin: 0px auto 0px auto;
height:auto ;
}