Hi,

Please check if this happens in Safe Mode. You can also try to manually Disable suspicious Extensions in Tools > Addons. If the problem persists, please see this.

Do a malware check with some malware scanning programs on the Windows computer.
You need to scan with all programs because each program detects different malware.
Make sure that you update each program to get the latest version of their databases before doing a scan.

• http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware
• http://www.superantispyware.com/ - SuperAntispyware
• http://www.microsoft.com/security/scanner/en-us/default.aspx - Microsoft Safety Scanner
• http://www.microsoft.com/windows/products/winfamily/defender/default.mspx - Windows Defender: Home Page
• http://www.safer-networking.org/en/index.html - Spybot Search & Destroy

You can also do a check for a rootkit infection with TDSSKiller.

• http://support.kaspersky.com/viruses/solutions?qid=208280684

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

Thank you dumdidadida and cor-el for your answers. I tried everything you both said (beginning from "safe mode" and the rest in order), none of them worked until I installed "Adblock Plus" add-on which I found from "Spyware on Windows" link! That ad is now completely gone. Thanks!

I too am having this problem. I downloaded the ad block plus ad on and it still did not stop these ads. Is there another ad block plus I'm supposed to download to stop the ads.