One of your tables has used <th>; if you change this to <td> the
<div id="TabbedPanels1" class="TabbedPanels"> with the links Featured, News, Tutorials etc will move over to the left. Browser treat th differently from td, usually centralising th but in this case it seems to be stopping it from aligning left.
Code:
<table width="1150" border="0" align="center" bgcolor="lime">
<tr>
<td width="1144" scope="col"> <!--THIS WAS th-->
<table width="320" height="201" border="0" align="right"
bgcolor="green">
<tr>
<th width="288" height="69" scope="col">
<div class="style21">
<p align="left">Tutorials</p>
<p align="left"> </p>
<p> </p>
<p> </p>
<p> </p>
</div>
</th>
</tr>
</table>
<p> </p>
<p align="right"> </p>
<p> </p>
<p> </p>
<p align="center"> </p>
<p align="center"> </p>
<table width="314" height="361" border="0" align="right"
bgcolor="skyblue">
<tr>
<td width="282" height="262">
<div align="center">
<script type="text/javascript"><!--
google_ad_client = "pub-2868005597213710";
//250x250, created 1/9/08
google_ad_slot = "9759247162";
google_ad_width = 250;
google_ad_height = 250;
//--></script>
<script type="text/javascript"
src="http://pagead2.googlesyndication.com/pagead/show_ads.js
">
</script>
>
</div></td>
</tr>
</table>
<p align="center"> </p>
<p align="center"> </p>
<p align="center"> </p>
<p align="center"> </p>
<p align="center"> </p>
<p align="center"> </p>
<p align="center"> </p>
<p align="center"> </p>
<p align="center"> </p>
<p align="center"> </p>
<div id="TabbedPanels1" class="TabbedPanels">
<ul class="TabbedPanelsTabGroup">
<li class="TabbedPanelsTab" tabindex="0">Featured</li>
<li class="TabbedPanelsTab" tabindex="0">News</li>
<li class="TabbedPanelsTab" tabindex="1">Tutorials</li>
<li class="TabbedPanelsTab" tabindex="0">Videos</li>
<li class="TabbedPanelsTab" tabindex="0">Kewl
Stuff</li>
.................<!--edit end tag from </th> to </td> later-->
It's probably not the whole answer, the code is very complicated and I haven't had time to study it all, but if the links and content underneath move across, it must be the main problem located.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.