Category Drop Down broken in IE

I’ve been looking everywhere but I can’t seem to find anyone else who has had this problem. . . .

To begin, I’m a student at Missouri Southern State University and I work in the ITS department. We are currently using WordPress as a CMS for the ITS department’s pages. https://www.mssu.edu/its

The Problem: Using IE (7.0 and below) The category drop down menu on the homepage will not work. It acts like it’s just refreshing the page. Looking at the url it is correct, but IE won’t display it. If I copy the url and paste it in firefox it displays correctly.

Any help or ideas would be appreciated!!!