From what I have been reading from other posts on this forum, the issue may be caused by the clear history settings.

Press the <Alt Key> to bring up the tool bar. Then Tools > Options > Privacy. The button next to History, select Use Custom Settings.

At the bottom of the page, turn on Clear History When Firefox Closes. At the far right, press the Settings button. Turn on ONLY Cache and Form And Search History leaving the others off.

https://support.mozilla.org/questions/997866?esab=a&s=&r=1&as=s {web link} This is not a cure but will make it easier if Firefox locks up.

Thank you for the suggestion. But I cannot do as you had suggested because I want Firefox to maintain the history even when it closes. However let me understand the basic difference between browsing & download history and Form and Search History and then decide about your suggestion. Still, I am thankful for the effort taken to make the suggestion.

The settings above will only remove what is selected in the Clear History > Settings menu.

Cache; web page data is stored here. Sometimes when web pages don't load properly, clearing the cache can fix the problem.

Form And Search History; When you enter information in a web page, that information is stored here.

I have done what you have suggested. Tks for the clarification. I now understand better. However, I have also run Malwarebytes Anti Malware as well as Norton AV in safe mode, full system scan. A rather intense and deep scanning, which threw up some malwares, both PUPs and a Trojan. I feel an overall improvement in the system now.

Important : I ran Malwarebyte, after running their additional utility by the name Chameleon, which runs at command prompt.

Yet another input obtained from ESrepair. i.e. erasing unwanted dlls from windows memory. It is possible that the process explorer.exe is triggered by an unwanted dll. Just doing some more research, before deciding to try it out.

Shall continue to post useful info/insight.

Tks once again for the sensitive clarification vis-a-vis custom settings for clearing histories.

I note you said

Thank you for the suggestion. But I cannot do as you had suggested because I want Firefox to maintain the history even when it closes.

The problem we were discussing arises when History is cleared at closedown.

The default is to NOT clear history at close down.

The workaround is to not set Firefox to clear History when it shuts down, instead set it to remember History.

• Use New Button -> Preferences -> |Privacy| History Firefox will: [Remember History v]
• Note many users with this problem do not want to save information in which case consider using a Private Browsing window.
  You may need to close that window before exiting from Firefox
  Private Browsing - Use Firefox without saving history

I have also run Malwarebytes Anti Malware as well as Norton AV in safe mode

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

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• TDSSKiller - AntiRootkit Utility
• Hitman Pro
• ESET Online Scanner

Microsoft Security Essentials is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Did this fix your problems? Please report back to us!

Status Reporting :

Since last 2/3 days the problem reported i.e. Firefox Not Responding, primarily due to unresponsive Shockwave Flash player and/or various scripts, and, the duplication of running application in windows task manager has not occurred.

As a part of my attempts I should mention the two which I think might have a bearing in the status.

1. Constantly running Malwarebyte and NAV, atleast once a day. 2. As suggested by you I have opted for custom settings and did the following.

At the bottom of the page, turn on Clear History When Firefox Closes. At the far right, press the Settings button. Turn on ONLY Cache and Form And Search History leaving the others off.

Will report if I can understand/confirm more.