Try using the Search Reset extension.

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

This add-on is very simple: on installation, it backs up and then resets your search preferences and home page to their default values, and then uninstalls itself. This affects the search bar, URL bar searches, and the home page.

I'm sorry but it didn't do anything at all. Firefox without private browsing works. Also if I start Firefox without private browsing and I open a private window it works. But I got tired of that because it became very tedious.

You can check if you have the XML files of the default search engines including Google in the browser\searchplugins folder in the Firefox application folder.

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

If not then you need to reinstall Firefox.

• http://www.mozilla.org/en-US/firefox/all.html

Try to delete the search.json file and a possible search.sqlite file in the Firefox profile folder to reset the search engines to the default.

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

Firefox will rebuild the search.json file from the default search engines in the "browser\searchplugins" folder in the Firefox program folder and the searchplugins folder in the Firefox profile folder.

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder

Thank you, I'll try these solutions tomorrow because it is late right now. Thank you for your help.

You're welcome

Current Firefox versions use the default search engine (pref: browser.search.defaultenginename) to set the search engine that is used on the about:home page.

Check the browser.search.defaultenginename pref on the about:config page and make sure that it is set to the default value Google.

• browser.search.defaultenginename

Currently selected search engine:

• browser.search.selectedEngine

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