Help! Style doesn't seem to be working properly on single.php

Hello-
Please check out my site http://www.BucksHappening.com. I recently had to update my theme because of the Tim Thumb debacle (a chmod 777 that Tim Thumb used to auto size pictures for the theme was being abused by a hacker), and ever since we have been experiencing the following issue: the style of the site is fine until you click into a single post. At that time, the font changes, and the drop downs on the menus disappear. It doesn’t seem to happen all the time.

I am on a Mac, using Firefox 6.0. My sister checked it on IE on a pc and the issue exists there as well. I also check in safari. The font seems to stay but the dropdown menus still disappear within a post.

Help!! Many thanks.