It sounds as though Windows is detecting the problem, since you get the Windows crash dialog instead of Firefox's own crash dialog.

Have you noticed any pattern in this problem?

Here are a couple of things to try:

(1) Disable Firefox's use of hardware graphics acceleration

orange Firefox button (or Tools menu) > Options > Advanced > General mini-tab

Uncheck the box for "Use hardware acceleration when available"

This will take effect after you exit and restart Firefox.

(2) Disable the protected mode feature of the Flash Player plugin

In some configurations, this security feature can cause instability or hang Firefox with repeated dialogs about scripts not running well.

The following pages provide information on how to disable the protected mode feature.

• Adobe support article under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?

• Manual steps: https://support.mozilla.org/questions/968190?page=5#answer-509209

• Batch file: https://support.mozilla.org/questions/982093#answer-518078

If you discover pages that cause this problem regularly, you might try visiting them in Firefox's Safe Mode. That's a standard diagnostic tool to bypass interference by extensions, bugs in the JavaScript copilers, and problems with some custom settings. More info: Diagnose Firefox issues using Troubleshoot Mode.

If Firefox is running, you can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

If Firefox is not running, hold down the Shift key when starting Firefox

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

Any difference?

Thank you for your immediate response. I followed your instructions and initially it seemed that everything was fine. Until today. It happened again. Any suggestion?

It is possible that your security software (firewall, anti-virus) blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/kb/Server+not+found
• https://support.mozilla.org/kb/Firewalls

• https://support.mozilla.org/kb/fix-problems-connecting-websites-after-updating

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Do a malware check with some malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.
All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender: Home Page:
  http://www.microsoft.com/windows/products/winfamily/defender/default.mspx
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

Unfortunately it crashed again twice

ant continues crashing again and again...please help

Can you start Firefox in Safe Mode?

You can use one of these to start Firefox in Safe Mode:

• On Windows, hold down the Shift key while starting Firefox with a double-click on the Firefox desktop shortcut
• On Mac, hold down the Options key while starting Firefox

• https://support.mozilla.org/kb/Safe+Mode

Yes I can star Firefox in safe mode

In Firefox Safe mode these changes are effective:

• all extensions are disabled
• default theme is used (no persona)
• userChrome.css and userContent.css are ignored (chrome folder)
• default toolbar layout is used (localstore-safe.rdf)
• Javascript JIT compilers are disabled (prefs: javascript.options.*jit)
• hardware acceleration is disabled

• plugins are not affected
• preferences are not affected

Try yo create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I followed the instructions for creating new profile and everything was fine until now. It just crashed. Thanks for being so supportive

Is there still no crash report send (i.e. no entries on about:crashes)?

It is possible that some web page trigger the crashes.

Try to rename (or delete) the sessionstore.js file and possible sessionstore-##.js files with a number and sessionstore.bak in the Firefox profile folder.

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Multiple_profile_files_created

Deleting sessionstore.js will cause App Tabs and Tab Groups and open and closed (undo) tabs to get lost and you will have to recreate them (make a note or bookmark them if possible).

You can set the Integer pref browser.sessionstore.max_resumed_crashes to 0 on the about:config page to get the about:sessionrestore page immediately with the first start after a crash has occurred or the Task Manager was used to close Firefox.

• http://kb.mozillazine.org/browser.sessionstore.max_resumed_crashes

You can open the about:config page via the location bar.

• http://kb.mozillazine.org/about:config

That way you see if the previous session didn't close properly or crashed and will allow you to deselect the tab(s) that you do not want to reopen, but will allow to reopen other tabs. See:

• http://kb.mozillazine.org/Session_Restore#Restoring_a_session_after_a_crash
• http://kb.mozillazine.org/browser.sessionstore.max_resumed_crashes

I am not sure whether it is some pages that cause the problem. So, I followed your instructions renaming the above mentioned files and changing the value to 0. On purpose I left the browser open in this page (support mozilla) and after an hour crashed again. Then I had the option to deselect the only tab that was open, the one of the Mozilla support