Hi, just to clarify, Google and Bing are search engines which can be used on Firefox browser. More - [[Use the search bar in Firefox]]. You can also set Firefox as your default browser if you wish, although it can always be opened anyway, by clicking on the Firefox icon on your Desktop or Taskbar. More - [[Make Firefox your default browser]]. Should your search engine keep changing on its own, there may be another problem, so please post back if that is the case. ''If your question is resolved by this or another answer, please take a minute to let us know. Thank you.''