It might just be that your search bar (the bar to the right of the address bar) is set to Yahoo, try changing it back to Google. To do that, on the search bar click the icon or the down triangle to display the list of search engines, and select Google from that list. If that doesn't fix your problems, did you download Firefox from the official Mozilla site? Sometimes if you search on Google or any search provider, they sometimes have "Advertised links" which are sometimes Firefox bundles that have been slightly modified/shipped with malicious software. * https://www.mozilla.org/en-US/firefox/new/ * https://www.mozilla.org/en-US/firefox/all/ If you did download from a different website and believe that to be the cause, you can report the link here: * https://www.mozilla.org/en-US/about/legal/fraud-report/ -------------- Check your list of install programs in Windows - Control Panel > Programs and Features. Usually malware comes bundled with other applications, so if you sort by date and see several applications installed at the same day, it may be easier to find suspicious applications that way. You can try the [https://addons.mozilla.org/en-US/firefox/addon/searchreset/ Search Reset Tool]. It is an extension that will reset your home page, new tab and search settings back to the default then uninstall itself. If you find that its changes are being undone, please see the article [[How to fix preferences that won't save]]. If none of the above work, and you don't have too many extensions, you can also try the Reset Firefox feature which can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information. '''Note:''' After resetting Firefox, you will lose any extensions, toolbar customizations, and some preferences. See the [[Reset Firefox – easily fix most problems]] article for more information.