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: * [https://www.microsoft.com/en-us/wdsi/products/scanner Microsoft Safety Scanner] * [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware] * [http://support.kaspersky.com/viruses/disinfection/5350 Anti-Rootkit Utility - TDSSKiller] (for more info, see this [https://www.bleepingcomputer.com/download/tdsskiller/ alternate TDSSKiller download page]) * [https://www.malwarebytes.com/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] [https://support.microsoft.com/help/14210/security-essentials-download Microsoft Security Essentials] is a good permanent antivirus for Windows 7/Vista if you don't already have one. Windows 8/10 have antivirus protection [https://www.microsoft.com/windows/comprehensive-security built-in]. Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article. Did this fix your problems? Please report back to us!

''danemer [[#question-1256000|said]]'' <blockquote> Why am I getting multiple pop-unders with new 66.0.3 version? </blockquote> Vs Pop-ups? What's your Pop-Up settings in Options? ~Pj

"Block pop-up windows" - Checked '''''DU-UUHH!!''''''' Thanks anyway, though. ''[Signature link removed by moderator. Please read [[Forum rules and guidelines]], thanks.]''

You can do a malware scan. *https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

Sounds like a plan. We'll see how it goes. Thanks! ''[Signature link removed by moderator. Please read [[Forum rules and guidelines]], thanks.]''