Unfortunately, crash reports are not read immediately. To share them with us here on the forum, can you post the past several crash IDs in a reply? This article describes how to access them: Troubleshoot Firefox crashes (closing or quitting unexpectedly).

Here are the one's from July -

bp-44e16cba-8a1d-4a99-8e2e-1c15a2130715 7/15/2013 1:57 PM
bp-b4ee0cb7-4b9d-45a8-af7f-3ae172130715 7/15/2013 9:53 AM
bp-63f47f87-246f-4240-a184-1af352130715 7/15/2013 7:10 AM
bp-d51348fa-bc47-4459-ad66-bfb4d2130712 7/12/2013 12:36 PM
bp-fbf4f2c1-e170-412e-8215-6ff472130712 7/12/2013 8:48 AM
bp-adfabd4c-3cec-42fe-8ff1-b83c12130711 7/11/2013 11:32 AM
bp-c70c4c6e-51d7-48e5-a8b9-2d1662130711 7/11/2013 8:21 AM
bp-5b76fe51-0a87-433f-b94f-9d3612130710 7/10/2013 9:23 AM
bp-8542e23c-1497-43a2-9c5e-450042130709 7/9/2013 12:03 PM
bp-f6681961-4730-43c2-8d76-5a3a32130709 7/9/2013 8:13 AM
bp-32c677a8-0755-4e5a-90c8-e8dd52130708 7/8/2013 8:09 AM
bp-0f697409-7094-45e0-a494-2edeb2130703 7/3/2013 8:11 AM
bp-d1465262-4c60-4585-9b73-97ee02130702 7/2/2013 9:00 AM
bp-682231a9-15bb-437e-a778-2e2842130701 7/1/2013 11:22 AM
bp-083eacdc-dc2b-44af-a5e5-16e1f2130701 7/1/2013 7:31 AM

Some of the crash reports and related submissions and related bugs (I only read a few) refer to Firefox running out of memory. But that doesn't help get you to a solution.

I see you have disabled all plugins except Flash. How about extensions?

orange Firefox button (or Tools menu) > Add-ons > Extensions category

Could you also try Firefox's Safe Mode? That's a standard diagnostic tool to bypass interference by extensions (and some settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

That would help if I knew which page caused the crash and if it happened on a repeatable basis - for example, today it crashed when I opened the browser for my work e-mail, but that's not always that case so going back to disable add-ons would only tell me something was amiss if it always crashed on the same page.

Well, alternately, you could disable ALL nonessential extensions, i.e., the ones you can live without for 24 hours at see whether that changes anything during the next 24 hours.

You can do that here:

orange Firefox button (or Tools menu) > Add-ons > Extensions category

Then restart Firefox using one of the links provided for that purpose.

ok but what's that going to resolve? I have many things set up in terms of security, like ghostery, a google tracker blocker etc - part of the appeal with mozilla is the security add ons etc so if I disable them, what's the point? Not try to be snarky, but - to use the car analogy again - you're telling to shut off a feature that brought me to the product in the first place.

Hi angry_user, analogies are fun, but let me skip joke about the fuzzy dice and just say you can disable whatever YOU feel is nonessential and see whether it makes a difference. I'm not asking you to give up security or privacy if you don't want to.

it seems crashes were related to an add-on - NoScript

Hi angry_user, thank you for the update.

I'm not sure how NoScript was involved, but because many sites split their scripts between different servers, perhaps they went haywire when some of the scripts did not load. ??