You may have installed something "free" recently that loaded up your computer with adware (or worse). It's going to take a few steps to get it all cleaned up. (1) In the Windows Control Panel, Uninstall a Program, click the Installed On column heading to bring the latest installs up to the top. Here there probably are some thing you didn't realize were getting installed that you want to remove. (2) Restart Firefox in Safe Mode to temporarily disable extensions. This will make it easier to do the next things. ''If Firefox is running:'' Help > Restart with Add-ons Disabled ''If Firefox is not running:'' Hold the Shift key down when double-clicking the Firefox program icon Then in the small dialog that appears, click "Start in Safe Mode" (''not'' Reset) (3) Download and run malware cleaning tools. This article suggests ones that have worked for other Firefox users. Nearly all are free. [[Troubleshoot Firefox issues caused by malware]] (4) Remove suspicious add-ons. Either: * Ctrl+Shift+a * orange Firefox button (or Tools menu) > Add-ons In the left column, click Extensions. Then cast a critical eye on what you find. If in doubt, disable or remove these extensions. Usually a link will appear above at least one disabled extension to restart Firefox. Do Step #5 before restarting. (5) Remove the user.js file, because otherwise it will override your settings changes at startup. This article has the steps for that: [[How to fix preferences that won't save]]. (6) Restore Firefox default search engine, home page, and new tab settings. You could customize these manually, but this may be a faster option. https://addons.mozilla.org/en-US/firefox/addon/searchreset/ And... are we clean yet?