Currently this template is set to a width of 95% See the first line here:
http://www.practiceboard.com/?3380252
<table cellspacing="0" cellpadding="0" width="75%" align="center">
I changed the 95% to a 75% - you can adjust this to any number to make it fit the screen with the left nav bar
This is also a handy site to test how the page will work on different screen sizes:
http://www.anybrowser.com/ScreenSizeTest.html
Remember most buyers still use the 800x600 resolution!