Try installing [https://addons.mozilla.org/en-US/firefox/addon/searchreset/ https://addons.mozilla.org/en-US/firefox/addon/searchreset/]. It will reset your search to the default.

Reset the browser.startup.homepage_override.mstone pref via the right-click context menu to the default on the about:config page and close and restart Firefox to restore the about:home page to its default. * Open the <b>about:config</b> page via the location bar * Type in the Filter bar: mstone * Right-click the browser.startup.homepage_override.mstone line and select: Reset * Close and restart Firefox See also: *http://kb.mozillazine.org/about:config If that didn't help then delete the delete the chromeappsstore.sqlite file in the Firefox Profile Folder and repeat the above. ---- Start Firefox in <u>[[Safe Mode]]</u> to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance/Themes). *Don't make any changes on the Safe mode start window. *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes