My dad keeps getting them on his laptop, he has had a variety of AV software such as Norton/Trend Micro/MSE none of which seem to help. He only uses Firefox, everything is updated. (Unfortunately I cannot turn on NoScript as a lot of sites would be affected, I can't expect him to find out why a site doesn't work and whitelist it.) I've told him to ignore these popups and told him to never hit cancel but always close it with the 'x' but old habits die hard, and some of these damn popups even disable that and can only be dismissed by closing the website. What is an effective webpage filter to avoid these?