I don't know if this has been reported before but for the past couple of months I have not been able to use the Page Back button using IE9. Basically, nothing happens when I hit it. From what I can tell, Google Ads is the problem. For some reason, IE thinks every page visited on Head-Fi is http://googleads.g.doubleclick.net/page, so when I try to go back, it just stays on the same page.
I don't know if there is anything in the settings I can change but when I first started using IE9 I did not have this problem. Head-Fi is also the only site where this occurs and I'm sure others I visit also use Google Ads.