Do not think you are running any beta program as information sent shows you are running version 56 which is current. If had a beta before update that could be the issue. I do not run beta's and do not know how they update as that is done on the beta release channel.

These things you describe are a issue are not handled by Firefox but by your OS and Video Drivers. This is a old card 310M as I have one in my old laptop.

Think you need to save bookmarks/passwords/profile and uninstall Firefox and see how your system works without it. If system has issues you may have to use a Driver Update program (do not use iobit) as system is really old with that video card.

People with older machines and issues with Firefox are moving to the extended release https://www.mozilla.org/en-US/firefox/organizations/all/

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

I do not think you finished reading my post. If you had, you would see that everything you suggested I had already tried. And the reason you don't think I'm running the beta version is because I uninstalled it before sending the post. The problem is that if I uninstall Firefox altogether, my issue resolves itself and the issue returned when I reinstalled the normal current version 56 even though I had no problem before trying the beta version.

I agree with your other opinion: never try Firefox beta. Everything was fine before that, regardless of the age of my PC.

Well thought I read it as did not see any mention of video drivers. You said you uninstalled both but as said shows ver 56 so just confused.

I would suggest digging into your OS and deleting all folders but profile if needed and go into the registry and delete what you can find and after do below. Today try https://www.mozilla.org/en-US/firefox/all/ as it it now version 56.0.1

If/when return could you mention which version you are now running and what Extensions/plugins you have installed please.

Did you try the extended release ? If so any issues ?

Fyi: Firefox Quantum 57 to be released Nov14th.

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