You may have ad / mal-ware. Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article. ----------------- After the computer is cleaned; Bookmark and use this; Download the '''[https://addons.mozilla.org/en-US/firefox/addon/searchreset/ Mozilla Search Reset]''' {web link} 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.