Update - YouTube videos are playing fine in Safe Mode but not otherwise.

I have three plugins, OpenH264 Video Codec, Flash and Widevine Content Decryption Module. I set all to never activate but am still getting the black screen on YouTube.

I would think that this is your problem : adapterDescription: AMD Radeon HD 7660G + 7670M Dual Graphics driverDate: 1-23-2013 Up Date if you Can.

Set those back to default. Not the issue. Is possibly your Proxy Extension or your letting Ublock block to much. Disable one and test then the other, restart Firefox each time.

Safe mode ran without plugins/Extensions so there is the big time clue.

Please let us know if this solved your issue or if need further assistance.

Thanks for the reply. Windows is telling me I have the most up to date driver for the display adapter.

I removed the Proxy extension and disabled Ublock but still have the black screen. I don't know what other plugins or extensions I have!

Can try create a new Profile as it maybe corrupt https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

or go straight to this : 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. But you should make a back up before you do : https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Reinstall with Current Release Firefox 57.0 with a Full Version Installer https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

Phil Strictly said

Thanks for the reply. Windows is telling me I have the most up to date driver for the display adapter. I removed the Proxy extension and disabled Ublock but still have the black screen. I don't know what other plugins or extensions I have!

Windows will always tell you that especially if t has replaced the proper drivers with their own. Windows 10 can and will update your Hardware Drivers to there own. https://www.howtogeek.com/302595/how-to-stop-windows-10-from-automatically-updating-hardware-drivers/

This is a real pain when having cutting edge system, just install new drivers and reboot and then Windows changes them to something from 2006.

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block (wanted) content (e.g. Adblock Plus, NoScript, Ghostery, uBlock Origin) always make sure such extensions do not block (wanted) content.

• make sure your extensions and filters are updated to the latest version

• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Well, after I deleted and freshly reinstalled uBlock, two complete restarts seems to have solved the problem!

Thanks for all your help and suggestions.

Found a similar problem in my Fx57.03 Youtube can't be loaded as a frame when viewing outside Y2B Tried disabled uBlock Origin but no help Solution: Close the tracking protect in Fx's options. Either ONLY PRIVATE BROWSE or NEVER could help. Also, maybe it's caused only with the stricted Disconnet.me list.

Note that Firefox shows a shield icon in the location/address bar when Tracking Protection is blocking content. You can open the Web Console to see more detail.