A common cause of unresponsive script errors on Windows 7 is the protected mode feature of the Flash player plugin. That feature has security benefits, but seems to have serious compatibility issues on some systems. There is a hidden setting to disable it; I suggest trying this for a day to see whether it helps: (A) In a new tab, type or paste '''about:config''' in the address bar and press Enter. Click the button promising to be careful. (B) In the search box above the list, type or paste '''flash''' and pause while the list is filtered (C) Double-click the '''dom.ipc.plugins.flash.disable-protected-mode''' preference to switch its value from false to true. This might not take effect until all Flash has been unloaded for a few minutes, or you close Firefox.