Remove the adware software you have. I mean, adware softwares are small softwares which installs toolbars and changes search defaults. After that, try the "about:config" way. It must work. If it doesn't work, try to clean your history and regedit.exe and try again.

Hey,

please read the Troubleshoot Firefox issues caused by malware article and execute the steps mentioned therein.

--Tobbi

Step 1 :In the Location bar, type about:config and press Enter.

       The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise!, to continue to the about:config page. 

Step 2 : In the Search field, type keyword.enabled.

   Double-click the keyword.enabled preference to set its value to false. 

       https://support.mozilla.org/media/uploads/images/2012-09-11-12-48-42-2b9b31.png

Step 3 :Changing the Internet Keyword service

You can specify any valid URL to perform the Internet Keyword searches by modifying the keyword.URL preference in the about:config page:

   In the Search field, type keyword.url

        https://support.mozilla.org/media/uploads/images/2012-09-11-12-57-50-d8fea1.png

   To use Google search, right-click on keyword.URL and select Reset. 

   To use Yahoo!, set keyword.URL to http://search.yahoo.com/search?p=,

   For Bing, set it to http://www.bing.com/search?q= . Other services maybe specified similarly.
   

Note: The default Google search is encrypted to prevent eavesdropping. Switching to another search provider removes this protection.

http://www.google.com/#sclient=psy-ab&hl=en&site=&source=hp&q=

Now the search results come up in Google not in this other annoying search engine

November, 2012

Actually, the problem seems to have become a bit more entrenched.

So, now this 'malware (whatever its source is)' seems to be updating many more entries in the config file. If you want to retain the search functionality in the browser address bar, you can follow the below listed steps.

So ,here go the steps again -

Step 1 - Goto the browser address bar and type in 'about:config' . Press 'Enter' - Click through to the next page

Step 2 - In the Search field on top - Key in 'keyword.url' - Right-click - Select 'Modify' - Change to the search-engine that you want - as listed in the posts above

Step 3 - In the Search field on top - Key in 'browser.search' . RESET the values (by right clicking) of -

a) browser.search.defaultenginename

b) browser.search.order.1

The search function started working for me with my preferred search engine after these steps. Hope this helps.

You can also try to reset some preferences to the default with the SearchReset extension:

• https://addons.mozilla.org/firefox/addon/searchreset/

Note that the SearchReset extension only runs once and then uninstalls automatically, so it won't show on the "Firefox > Add-ons" page (about:addons).

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

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

(locking thread because of age)