You probably have malware or adware on your computer, possibly through someone using such sites on your computer. Try scanning with multiple and up to date software such as suggested under. Report back with how you get on and what you scanned with. -------- 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: * [http://www.microsoft.com/security/scanner/default.aspx Microsoft Safety Scanner] * [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware] * [http://support.kaspersky.com/viruses/disinfection/5350 Anti-Rootkit Utility - TDSSKiller] * [http://general-changelog-team.fr/en/downloads/viewdownload/20-outils-de-xplode/2-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] [http://windows.microsoft.com/MSE Microsoft Security Essentials] is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one. Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article. Did this fix your problems? Please report back to us!

FYI - https://support.mozilla.org/en-US/kb/block-and-unblock-websites-parental-controls-firef

'''[https://addons.mozilla.org/en-US/firefox/addon/webutation-reputation-security/ Webutation]''' {web link} Would you like to know which websites are safe and which website you can trust? The Webutation add-on shows you the reputation of a site with a simple green/yellow/red icon and scans websites against virus and bad userfeedback. Works similar to WOT. Settings Webutation; Block bad websites Block adult websites ------------------------------- '''[https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/ Adblock Plus]''' {web link} Blocks annoying video ads on YouTube, Facebook ads, banners and much more. Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).