I never had a problem with this before and it is confusing me!
Whenever I go to my messages in the hotmail inbox the Internet Explorer browser crashes because it looks like it is trying to load up an AD on something like that (blank white box retangular shape)
You can use a "hosts" file in Windows to block ad servers and spyware. It's worth doing. Google for hosts file block ad servers and look at the links, the first one is good. Download the hosts.zip file and follow the instructions. Soon, all hotmails ads will just be white rectangles with "Page not found" errors.