hi gary, can you please try to install the latest version of firefox 51 beta from https://www.mozilla.org/firefox/channel/#beta and see if you can still reproduce these crashes there? one other thing that might need your attention: your submitted data about firefox show that there is a leftover from an outdated and vulnerable flash plugin present on your system which can lead to problems. please use the uninstaller tool that adobe provides at https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html and install the plugin again after that...