Remove that slide show, clear your internet cache, and then see how it goes. When you put scripts or other things on your forum where they require the actions of an outside website, that can make problems with your forum, since if those other sites have a problem, your forum cannot load completely. I see that on that slideshow script, the background has a message "Image Unavailable". So maybe Internet Explorer was trying and trying to load everything fully, but it was an impossible task.
Always remove all scripts you have added and then see if your forum is fine. If it is, then you know there was a problem due to one or more of the scripts.