Do not set the table column's width to a fix value which contains the content control. For detail, that is remove the bold face settings shown in the following.
<td style="width: 25px; height: 283px" valign="top">"
entirely, the aspx code should be changed to the following.
<%@ Master Language="VB" CodeFile="MasterPage.master.vb" Inherits="MasterPage" %>
<!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">
<title>MasterPage</title>
<link href="StyleSheet.css" rel="stylesheet" type="text/css" />
</head>
<body style="font-size: 10pt; color: white; font-family: Tahoma" bgcolor="#7e90a7" alink="#ffffff" link="#ffffff" text="#ffffff" vlink="#66ccff">
<form id="form1" runat="server">
<div>
<table>
<tr>
<td colspan="2" style="height: 236px">
<asp:Image ID="Image1" runat="server" ImageAlign="Top" ImageUrl="~/Images/topF.jpg"
Width="980px" Height="227px" /></td>
</tr>
<tr>
<td style=" height: 283px" valign="top">
<asp:Menu ID="Menu1" runat="server" DataSourceID="SiteMapDataSource1" BackColor="White" Height="35px" Width="464px" ForeColor="#7E90A7" Orientation="Horizontal" DynamicVerticalOffset="5">
<DynamicHoverStyle BackColor="White" />
<DynamicMenuStyle BackColor="#7E90A7" />
<DynamicSelectedStyle BackColor="White" ForeColor="White" />
<DynamicMenuItemStyle BackColor="White" ForeColor="#7E80A7" />
</asp:Menu>
<asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server" ShowStartingNode="False" />
<br />
<asp:ContentPlaceHolder ID="Main" runat="server">
</asp:ContentPlaceHolder>
<br />
</td>
<td style="height: 283px" valign="top">
<strong><span style="color: #ffffff">Phone:
<br />
xxx-xxx-xxxx<br />
<br />
FAX:<br />
xxx-xxx-xxxx<br />
<br />
Address:<br />
withheld
<br />
<br />
E-Mail:<br />
withheld<br />
<br />
© Company Name. </span><a href="privpol.aspx"><span style="color: #ffffff">
Privacy Policy</span></a></strong></td>
</tr>
<tr>
<td style=" height: 18px;">
</td>
<td style="width: 145px; height: 18px;">
</td>
</tr>
</table>
</div>
</form>
</body>
</html>