Hello from BC. Sunshine Coast. Did you turn updating off so 56 will not update to 57 ? Also 56.0.2 is no longer safe to use for every day use, but 52.5.0 ESR is ! It will continue to get security updates until May 2018, and you can download and install it from this page: https://www.mozilla.org/en-US/firefox/organizations/all/ If you see something that says you need Flash look in the Address Bar for a blackish Lego Block and click that to grant permissions. I myself have not had that issue. I get places I go to and the video screen will be black saying I have to activate Flash, click there. Then the Blackish Lego Brick pops out a do you want to grant permission this site, yes and or remember this. Youtube uses HTML5 for their videos now. CBC did not ask me and if right click video it uses it's on CBC Caffeine Player https://cbchelp.cbc.ca/hc/en-ca/articles/217738818-What-are-the-system-requirements-for-playing-videos-on-the-CBC-website- Now could trouble shoot this for awhile or can go straight for the guts which is faster. Please uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. Then should install 52.5.0 ESR https://www.mozilla.org/en-US/firefox/organizations/all/ Now if this does not fix it try making a new profile and see what happens. https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles Also just noticed a few errors in your Video Card Information see if can update your drivers for NVIDIA GeForce GTX 1060 3GB https://www.geforce.com/drivers Corrupted and Old Drivers can cause a wide range of issues. Keep them updated, never know when support will end plus FF 57 needs it. Please let us know if this solved your issue or if need further assistance.