Hello,

Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Thank you.

Thank you, colbabomb. I tired Firefox safe mode and the issue persists, Bing prevails. ...

Hi mondaymorning, could you describe what's happening in more detail.

It sounds as though you are working with the built-in search box, which should allow you to choose any of the search engines by their icon. Is the problem that you can't choose one of the other icons in the search bar, or even if you do, you get a Bing results page?

There are some extensions that show their own search box either on the tab bar or possibly in place of Firefox's search bar. If you review your extensions, can you see any that have been installed recently? If none seem to be the culprit, try disabling ALL nonessential extensions and restart to see whether the behavior changes.

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

Which way(s) of searching are you referring to?

• searching via the location bar (pref: keyword.URL)
• search bar on the Navigation Toolbar
• search bar on the about:home page (pref: browser.search.defaultenginename)
• other search bar (e.g. added by extension)

If you do not keep changes after a restart then see:

• http://kb.mozillazine.org/Preferences_not_saved

You can check for malware or check if you have anything BIng Related installed by going to Control Panel> Programs and if there is, uninstall it.

MBAM - http://www.malwarebytes.org/products/malwarebytes_free/

Dear colbabomb, jscher2000 and cor-el, First of all, I sincerely thank you for your helps. Here is a debrief of what I’ve found as I followed your instructions. And, yes, to be clear, the Bing-dominating issue that I referred to occurs when I search via Mozilla’s built-in search box, the one on the navigation toolbar. • I don’t have any recently installed “extensions”. • My pref.js file is not read-only, nor does it seem to be locked. • After I replaced the pref.js file with my Dell’s pre-installed default pref.js file, an error message that says, “Not Found. The requested URL xxx was not found on this server”, popped out when I selected Google search engine from the Mozilla built-in search bar. The same error message went with the pref.js file that I copied from an old file before the FF20.0.1 upgrade. • The only Bing related program I had was installed five months ago. None of the programs installed within these two months seems suspicious. • No malicious items were found via Malwarebytes quick scan.

At this point I decide not to use Mozilla built-in search bar. I do have to say that, after being spoiled by the convenience it offers, being prevented from using it is not an optimal choice for me. So I wish to find a solution soon. Thank you again.

p.s. One interesting thing, which I don’t know if it is relevant, is that when I tried other browsers, e.g., Internet Explorer and Google Chrom, I noticed one same thing: Bing is the default search engine and MSN is the default homepage. Something has reset my browsers. I had a MS security update for W7 about four days before the FF upgrade.

Hi mondaymorning, this part is mysterious to me:

After I replaced the pref.js file with my Dell’s pre-installed default pref.js file, an error message that says, “Not Found. The requested URL xxx was not found on this server”, popped out when I selected Google search engine from the Mozilla built-in search bar. The same error message went with the pref.js file that I copied from an old file before the FF20.0.1 upgrade.

I'm surprised Dell has a file for Firefox at all. At this point, you may need to just remove prefs.js from your settings folder and let Firefox regenerate it from scratch.

When you changed icons on the search bar and ran your Google search, did it not go to google.com? Or it went to google.com but used a bad search URL?

Hi jscher2000, when I used the old pref.js files and ran the Google search from Mozilla’s built-in search bar, it did not go to google.com but popped out with the error message I mentioned earlier. I have removed the old pref.js files out of the setting folder and let FF generate it anew. With regard to the “Dell’s pre-installed default pref.js file”, it is indeed strange; I don’t know how it was there. ...