Heh, I was just reading in that thread about SC4 that you've almost reached 500, I opened your profile and you were on 499 then clicked 'last post' to find you on 500 🙂
Got an avatar ready? I went until about 700 posts before adding one 😱
Getting back on topic, I'd try deleting IE's pref files. If I remember correctly, there is a 'Microsoft' prefs folder.