Mal-ware can come from anywhere, and hide itself from anti-virus scans.

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

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:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• Anti-Rootkit Utility - TDSSKiller
• AdwCleaner (for more info, see this alternate AdwCleaner download page)
• Hitman Pro
• ESET Online Scanner

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!

Start Firefox in Safe Mode {web Link} by holding down the <Shift (Mac Options) > key, and then starting Firefox. Is the problem still there?

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).

put FF into safe mode, still see ads,

Related "question" thread from 2 years ago. https://support.mozilla.org/en-US/questions/953386

One user said "Adware cleaner works perfectly and free" - did you try using it?

after running eset online scanner for nearly 12 hours it found some stuff, but not the problem issue. downloaded and ran ADW cleaner THREE TIMES .. if found some stuff and took care of those also

still have the problem, in fact it appears to be worse!!!

from my stand point it appears that FF/Mozilla is condoning this company because it does not effect my IE or Chrome browsers.

my only alternative is to abandon FF and use the other browsers....note I have used FF almost from its inception and this is the way they treat their longtime users!!!!

Can you show us those ads?

Hello,

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