First step is to disable all nonessential, recent, and unrecognized extensions here:

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

If in doubt, disable it. Then restart Firefox.

To reset your search providers back to Google, you can use this add-on:

https://addons.mozilla.org/en-us/firefox/addon/searchreset/

(If you prefer to do it manually, we can go over the steps.)

That should work for search, but if other settings are affected, such as your home page or new tab page, please post back on those.

You can do a search on the about:config page for prefs that are referring to mywebsearch or the URL as you see appearing and reset them via the right-click context menu.

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

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

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

While you are tidying up your extensions you should also look at your plug-ins. MindSpark(in the My Web Search stable) and Conduit have been problems in the past. For information, Google for problems in these three add-ons. Also look in the Search Box above for many references.

I also did the same and got stuck with a nasty bug which has been difficult to shift. Firstly: I tried to type about:config in the 'search programs and files' box which is where this always used to be. I now know that I should have typed it in the search bar of the browser. Perhaps this could be stated for further users. Secondly: I did find the offending software in about:config and tried to remove it....but there is no way of doing this on the page from what I could see. So I gave it my best shot (???) and 'reset'. How was I to know if this was good or bad? It appears that this has done the trick and I guess I'll see after a few days.