I just had an issue with a Ford ad that would cover the entire page and had no visible Close button/box and would not go away on any forum page except home my account and that is all. It finally died (after about 5 min) but that is a long time to be stuck in ad land. I closed the browser many times and reloaded with the same effect although I did get to see 2 different ads. I later even tried clicking on it and it took me to a ford thingie but man that was annoying. Just an FYI the Ford ad does not like to let go.