Start Firefox in Troubleshoot Firefox issues using Safe Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes).
Don't make any changes on the Safe mode start window.
Thank you very much for the assistance. It looks like Ad Block was the culprit. Hopefully that will be fixed immediately, because I consider that to be an absolute necessity, and one of the biggest reasons I use Firefox.
Thanks again! I'll hope for a fix soon.