Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

You can check if there is an update for your graphics display driver and check for hardware acceleration related issues.

• https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

thanks; but that doesn't seem to be where the problem is originating.

Did you try Safe Mode?

Separate Issue; Your System Details shows;

Installed Plug-ins

Shockwave Flash 18.0 r0 Shockwave Flash 14.0 r0 Shockwave Flash 13.0 r0

Version 0.9.19, Copyright 2006-2012 Veetle Inchttp://www.veetle.com/ Version 0.9.18, copyright 2006-2010 Veetle Inchttp://www.veetle.com/
Having more than one version of a program may cause issues. You must remove the older programs. Then get the current full installer.

Flash: Grab the uninstaller from here: Uninstall Flash Player | Windows Uninstall Flash Player | Mac

Then reinstall the latest version.

Flash Player Version 18.0.0.160
https://www.adobe.com/products/flashplayer/distribution3.html

Thanks for the help......