New ads appear in youtube and amazon. Adblock Plus doesnt work

Question

In the last week ads appear when I search on Amazon and YouTube. Usually Adblock Plus has worked but this time they are not blocked.
I can't tell who is doing this and I haven't installed any new software recently so I have no idea why this is happening. If I search for Lego, I get Lego offers from other sites. However, on youtube the ads can be more unsuitable.
Please help as some of the images are very unsuitable for my 5 year old.
Thanks,
Peter

Answer 1

Sometimes a problem with Firefox may be a result of malware installed on your computer that you may not be aware of. First check your home page settings to make sure nothing was appended (if there is a | followed by another link, that tells Firefox to open another tab with that link):
* Tools (or [[Image: New Fx Menu]]) > Options > General
Also check your add-ons for any suspicious extensions:
* Tools (or [[Image: New Fx Menu]]) > Add-ons > Extensions
Check your list of install programs in Windows - Control Panel > Programs and Features. Usually malware comes bundled with other applications, so if you sort by date and see several applications installed at the same day, it may be easier to find suspicious applications that way. Note that some applications bundle potentially unwanted programs in updates as well (such as some P2P applications).
You can also try the Reset Firefox feature which can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information. Note: After resetting Firefox, you will lose any extensions, toolbar customizations, and some preferences. See the [[Reset Firefox - easily fix most problems]] article for more information.
You can try these free programs to scan for malware, which work with your existing antivirus software:
* [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware]
* [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.microsoft.com/security/scanner/default.aspx Microsoft Safety Scanner]
* [http://support.kaspersky.com/viruses/disinfection/5350 Anti-Rootkit Utility - TDSSKiller]
* [http://www.surfright.nl/en/hitmanpro/ Hitman Pro]
* [http://www.eset.com/us/online-scanner/ ESET Online Scanner]
Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article.