Firefox 7.0.1. Windows7 Pro 64. Yesterday I was streaming audio from sky.fm and noticed that the navigation toolbar back arrow stopped responding and has not responded since. FF restart, computer reboot, same problem. Private browsing has never been used, i.e. the history file is fine. Using it is the only way to go back to a previous page or site. The only visual indication that the arrow has been clicked is that the firefox icon in the tool tray dims. All other indications are normal. The present url is displayed, and FF is responsive to any link clicks going forward--just not back. Any ideas? Thanks, John.