There are two types of pop-up. One type is generated by a website when you visit it but the pop-up blockers that are generally installed
by default in modern browsers, to prevent you seeing them. So I doubt that Gizmonster's post is relevant.
The other type of pop-ups aren't generated by the websites which you're visiting but by MALWARE on your computer. I'd be prepared to bet that's what's causing your problem.
Download, install and run the free version of Malwarebytes Anti-Malware:
https://www.malwarebytes.org/antimalware/
(NB: During the installation process you'll be offered a free trial of the Premium version. The box will be pre-ticked. Click to remove that tick!)
Don't be surprised if a scan takes ages to run. (Possibly over half an hour). That's normal. When malware is found (as I'm sure it will be) use the 'Quarantine' option to zap it.