Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of. You can try these free programs to scan for malware, which work with your existing antivirus software: * [https://www.microsoft.com/en-us/wdsi/products/scanner Microsoft Safety Scanner] * [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware] * [http://support.kaspersky.com/viruses/disinfection/5350 Anti-Rootkit Utility - TDSSKiller] (for more info, see this [https://www.bleepingcomputer.com/download/tdsskiller/ alternate TDSSKiller download page]) * [https://www.malwarebytes.com/adwcleaner/ AdwCleaner] (for more info, see this [http://www.bleepingcomputer.com/download/adwcleaner/ alternate AdwCleaner download page]) * [http://www.surfright.nl/en/hitmanpro/ Hitman Pro] * [http://www.eset.com/us/online-scanner/ ESET Online Scanner] [https://support.microsoft.com/help/14210/security-essentials-download Microsoft Security Essentials] is a good permanent antivirus for Windows 7/Vista if you don't already have one. Windows 8/10 have antivirus protection [https://www.microsoft.com/windows/windows-defender built-in]. Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article. Did this fix your problems? Please report back to us!

Also, in case they aren't detected as malware, check for bad add-ons. 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. Then cast a critical eye over the list on the right side. Any extensions required for Firefox 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. Any improvement?