experience - you are not the first one;
with the IE not showing all of the content, and/or sidebar missing or broken, one of the most likely causes is:
a. pasted Word
b. missing divs
c. broken style css
check where the content ends in IE, then look into the html code in the browser: 'View' 'Source' to find the spot.
that was already enough with your problem.
use firefox and the web developer add-on - that gives you an extra toolbar above the browser window, and gives insight into css and html, and lets you 'play' with the code 'online'
and use http://validator.w3.org/, to get more details about messed up html code, missing divs etc.