Hi &nbsp; ! Would you please take a look at these articles : https://support.mozilla.org/en-US/kb/pop-blocker-settings-exceptions-troubleshooting But most of all : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware '''Note : make sure that you run all, or at least most of the malware scanners.''' Just to be on the safe side, you may also want to do this : Go to the 3-bar menu => Addons => and look for any unfamiliar or suspicious looking extensions. When you find any : &nbsp; remove them. Also look in : &nbsp; Advanced => Network tab => Under : 'Offline Web Content and User Data' When you see something suspicious : remove it. Do the same in Windows' Control Panel => Programs. However : &nbsp; most malware will be 'hiding' somewhere, hence the malware scans. To prevent this from happening again you might consider installing this <BR>add-on : https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/