Hi Technomed. I've included a screenshot of the plug-in(s) you have running on your system that Firefox is using. To my knowledge, Firefox does not come pre-loaded with any plugins or extensions. I would recommend you consider troubleshooting extensions/add-ons, as they are just as likely, if not more likely, to be the cause of your issue(s). I've provided a link below that can help you identify problematic extensions/add-ons. I hope this has helped.

How to best troubleshoot extensions/themes/hardware acceleration: https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

You might also consider downloading a copy of Malwarebytes free version and running a scan, which would give you piece of mind at the very least.

Link: https://www.malwarebytes.com

Thanks Fiz, Your reply led me to further research my problem. In addition to Shockwave Flash that you mentioned, I also have: "OpenH264 Codec provided by Cisco Systems, Inc." and "Widevine Content Decryption Module provided by Google Inc". I found a good explanation of them detailed at: https://support.mozilla.org/en-US/questions/1128690.

Basically, my existing programs automatically loaded them in FF Plugins....so they're not malware after all.

Glad you were able to sort that out. Feel free to mark the question as solved, or let us know if you require any further assistance.