New facebook chat issue?

This isn't about chat errors or people sending me spam or anything. whenever i open a new IM window or someone IMs me on facebook, my computer freezes and my clicker changes into the way it looks when its loading something for a long time. this problem doesnt stay localized on facebook, it slows down all process on my computer, unless i close the chat or facebook. if i close the facebook window and go back to it, there are no IM windows shown even if i was chatting with someone and didnt close the specific IM before.