Yes of course. You can use whatever you like.

Hi, Yahoo is not included with Firefox. It may have been injected by an add-on, but you didn't share your add-ons list, so here's how to investigate that on your own Firefox: (1) Assess the scope of the problem ''Where does Yahoo appear?'' * A Yahoo page appears at startup * A Yahoo page appears in a new window (Ctrl+N) * A Yahoo page appears in a new tab (Ctrl+T) * Yahoo only appears when running a search through Firefox's address bar or one of its search boxes (2) Check extensions You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either: * Ctrl+Shift+a (Mac: Command+Shift+a) * "3-bar" menu button (or Tools menu) > Add-ons * type or paste '''about:addons''' in the address bar and press Enter/Return In the left column of the Add-ons page, click Extensions. On the right side, find the "Manage Your Extensions" heading. ''If there is at least one extension before the next heading -- "Recommended Extensions" -- please continue:'' Then cast a critical eye over the list below that heading. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious or that you just do not remember installing or why? If in doubt, disable (or remove). For your privacy and security, don't let mystery programs linger here. Any improvement? '''Note:''' Some especially evil add-ons seem to block access to the extensions list. If you can't see it, you can try the above steps in Firefox's Safe/Troubleshoot Mode. In that mode, Firefox temporarily deactivates extensions, as well as a few other advanced features. To get there: ''If Firefox is running:'' You can restart Firefox in Safe/Troubleshoot Mode using either: * "3-bar" menu button > Help > Troubleshoot Mode... (before Fx88: Restart with Add-ons Disabled) * (menu bar) Help menu > Troubleshoot Mode... (before Fx88: Restart with Add-ons Disabled) and OK the restart. A small dialog should appear. Click the Open button (before Fx88: "Start in Safe Mode" button). ''If Firefox is not running:'' Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.) A small dialog should appear. Click the Open button (before Fx88: "Start in Safe Mode" button). ''Note: Don't use the Refresh without first reviewing this article to understand what will be deleted:'' [[Refresh Firefox - reset add-ons and settings]]. Can you regain control of your searches? (3) Articles for restoring preferred settings after cleaning out bad guys * [[How to set the home page]] * [[Change your default search settings in Firefox]]