Did this problem just start recently? If so, did it happen around the same time as any software updates, whether to Firefox, an add-on, or Windows?

Could you try disabling extensions you can live without for 24 hours? I think it's safe to keep Adblock Plus enabled. Open the Add-ons page using either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then, if in doubt, disable.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Does that have any effect on the crashes?

I disabled all the add-ons,except adblock and avast security. Still It crashes.

Crash ID:bp-347d6220-8b7e-4ee7-b971-dd1b72150419

If you need more information let me know.

You might want to also disable Avast.

I can't tell exactly what Firefox is trying to do when it crashes, but it seems related to memory allocation/deallocation. I think it's beyond my limited expertise to suggest next steps for that.