This problem has shown up in the last couple versions of Firefox, but never in the earlier versions. Firefox will start and run normally for perhaps half an hour. Then it suddenly goes into a "reload loop" - the little "Reload Current Page" circular arrow goes around and around as if I had asked for reloads, even if no page load or reload has been requested. Firefox does not respond to keyboard or mouse inputs. I have to invoke the Task Manager to shut down Firefox. I then Restart the computer, and everything is fine until next time. If Thunderbird is running, it develops the "Thunderbird is processing the account - please wait" error at the same time that Firefox begins its error. However, Firefox has the same problem even if Thunderbird is not running. Because the problem seems to affect two programs, I first assumed that the OS was corrupted. I did a complete "upgrade from Win 7 to Win 7" using the reinstall disk that came with the computer. No help. I allowed Win 7 to do the massive number of Updates to bring Win 7 up to the current version. They completed successfully - and the problem is still with me. Then, because both programs are from Mozilla, I uninstalled and re-installed both programs again. The error continues. No other application programs appear to be part of this problem. Is it likely that something in my Mozilla Profile folder is causing this? Thanks for any help. Bill