Start Firefox in <u>[[Safe Mode|Safe Mode]]</u> to check if one of the extensions ("3-bar" menu button/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem. *Switch to the DEFAULT theme: "3-bar" menu button/Tools > Add-ons > Appearance *Do NOT click the "Refresh Firefox" button on the Safe Mode start window *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes You can check for problems with preferences. Delete possible user.js and numbered prefs-##.js files and rename/remove the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases. *http://kb.mozillazine.org/Preferences_not_saved *http://kb.mozillazine.org/Resetting_preferences You can use this button to go to the current Firefox profile folder: *Help > Troubleshooting Information > Profile Directory:<br>Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder *http://kb.mozillazine.org/Profile_folder_-_Firefox ----- Do a malware check with several malware scanning programs on the Windows computer. *https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware Please scan with all programs because each program detects different malware. All these programs have free versions. Make sure that you update each program to get the latest version of their databases before doing a scan. *Malwarebytes' Anti-Malware:<br>http://www.malwarebytes.org/mbam.php *AdwCleaner:<br>http://www.bleepingcomputer.com/download/adwcleaner/<br>http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml *SuperAntispyware:<br>http://www.superantispyware.com/ *Microsoft Safety Scanner:<br>http://www.microsoft.com/security/scanner/en-us/default.aspx *Windows Defender:<br>http://windows.microsoft.com/en-us/windows/using-defender *Spybot Search & Destroy:<br>http://www.safer-networking.org/en/index.html *Kasperky Free Security Scan:<br>http://www.kaspersky.com/security-scan You can also do a check for a rootkit infection with TDSSKiller. *Anti-rootkit utility TDSSKiller:<br>http://support.kaspersky.com/5350?el=88446 See also: *"Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

After the problem is fixed, 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.