I have a desktop with Windows 7, Norton, Firefox 42, Thunderbird, Flashplayer 19.0.0.245 NPAPI and Java 8. I never had a problem with YouTube till early Nov. ’15. (I don’t know if that coincides with the upgrade to 42.) Youtube opens and loads fine and plays perfectly for 2+ minutes before starting to hang and gets worse and finally freezes - and I get the ‘Firefox crashed’ notice. I’ve spent ~20 hrs trying online suggestions with no change, let alone improvement. That includes: unchecking Shockwave Flash Protection and hardware acceleration; disabling all add-ons; clearing history, cache and cookies; refreshing Firefox; downloading Firefox 42 again. I rebooted after these changes. Things I’ve NOT tried: I couldn’t get Firefox to go into Safe Mode; I’ve not downloaded other browsers; people online mentioned updating drivers, installing Media Feature Pack; possible firewall interference. I’ve been to places in my computer I never knew existed (and don’t understand). I’m 79 and didn’t want to spend my Golden Years this way! I don’t want to, but am considering reverting to Firefox 41.0.2. (My wife, on the other hand, has Firefox 42 with no Youtube issues…) Please help.