Hi, If you downloaded Firefox from anywhere other than mozilla.org it may have come bundled with unwanted junk. 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] '''Note that not all removal programs will detect all malware, so you may need to run several or all of them.''' Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article. Did this fix your problems? Please report back to us. Thank you!

Followed advice but problem persists. I downloaded from the official site. I can only avoid the ad by right click and going on private window

OK, open the Add-ons Manager (Ctrl+Shift+A) > Extensions/Plugins and look for it there. Also right click the Start button on your PC > Control Panel > Programs, and if it's there, uninstall it. You can also do a search for it in your PC's search box.