There are three areas in the page that may be affecting the page width:
1 - This line:
<div class="Section1" style="WIDTH: 998px; HEIGHT: 971px">
sets the minimum page width to 998px plus the width of the left shared
border and spacer column. I would remove the width and height from the
<div> tag.
2 - There is a line of non-breaking spaces. ....
where someone leant on the space bar. Remove that code, it does nothing
except make a very long line that will not wrap.
3 - Text "centred" using <blockquote>s. Remove the <blockquote> tags, and
the corresponding </blockquote>s. Centre the text using the formatting
buttons on the toolbars.
Finally, you may wish to revisit the use of Hover buttons for navigation.
New installations of IE6 and Windows XP will not be able to see them, or use
the navigation provided by them. I switched to a PC running Linux to be
able to navigate your site, since my Windows XP PCs do not have the required
JVM.