Most browsers have a pop-up blocker. You really shouldn't rely on norton to stop pop-ups.
In all browsers, there are pop-up settings. Mozilla and Chrome both have them set to medium to begin with. You can crank them up to "High" in the settings, and they will then block all pop-ups. If something gets past that, it used a script they haven't been updated to block.
Norton isn't really even the best anti-virus.
There are a lot of ways that pop-ups occur. Some are web oriented, ie you go to a website, and the scripting of the page prompts it. Some are client side...ie you go to the webpage, and it prompts a program stored locally on your computer to pop things up. Either method has about ten billion different scripts, and local programs, that result in the same issues. Even when programs like Norton, or web browsers figure them out, the people designing them just figure out new ways to get them to work again anyway. Essentially the programs are mechanical, they look for XYZ, and if someone makes it so there is a W it won't catch it, until they update their software. Then....they just make a Q script, and so on.
Unfortunately, without knowing what sites you're concerned about, it's difficult to tell what type of pop-ups you're getting. If you have a huge problem with pop-ups, I can deduce the following things:
1) You are going to a lot of shopping websites.
2) You are going to a lot of porn websites.
Mozilla and Chrome both have fairly good pop-up blockers. Just search the options and turn the security up. They won't ever, ever, ever, stop everything, but they can be "Fairly" accurate.
Second option, don't visit the two places I told you above :
There are plenty of porn sites that do not use popups, and plenty of legit shopping sites as well. Digging "Dirty deep", will lead you to basically the ghetto of the Internet. Pretend a pop-up assault is like getting caught down town in a bad city. The crappier the website, the more likely you'll find spyware, viruses, and pop-ups.
If you're using Internet Explorer, you are basically at a caveman level of the Internet. Don't use Internet explorer. It's the most exploited browser in the world.
Go google Chrome or Firefox. Internet Explorer is absolutely slow, and horrible.
I'll help you out if you need it. Just email me.