Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

Type about:support in the address bar and press Enter. Under the main banner, press the button; Copy Text To Clipboard.. Then in the reply box at the bottom of this page, do a right click in the box and select Paste. This will show us your system details. No Personal Information Is Collected.

Thanks for you help! When I state Firefox in safe mode, I still get the flash screen - but it lingers for maybe a half second longer than when starting normally.

Could you read it?

Good point. I did a screen capture and was able to isolate this - achieved in safe mode.

Start your Computer in safe mode with networking. Then start Firefox. Try Safe websites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

Yes it is. (even in safe mode w/o networking)

I called for more help.

Fred - I appreciate you help!

Did anyone answer your call ? Just wanted to make sure I didn't get lost on hold. Thanks!

I placed another call.

Sooo . . .

Should I take no response as a lack of interest, or a lack of solution?

Sorry  :-(

I appreciate your help. It's suspicious - as if there is something running in the background. Must be the Russians ;)

Use these links to create a new profile. Use this new profile as is. Is the problem still there?

http://kb.mozillazine.org/Profile_folder_-_Firefox#Navigating_to_the_profile_folder

https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

Type about:profiles<enter> in the address bar.

Fred - I created a new profile and opened firefox in that profile. Same thing!

:(

My last suggestion would be;

You may have ad / mal-ware. Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

Appreciate it. Nothing found/changed :) I'm going to do a fresh OS install.