Annoying new variety of pop-ups

I've noticed some intrusive new type of pop-up in the past 2 days. They don't have an "x" to kill them and they move, sometimes blocking the text you are trying to read, when you are scrolling down the page.

I was able to kill one yesterday that was driving me nuts by clicking on it, adding the web address to my 'block' list, then clearing my private data. Good news is that it hasn't been back.

But, today there is a new one that showed up, from a different web site, while I was reading news from CNN.

I have a Norton Firewall and use Mozilla. I've run a full system scan to try and make sure I haven't picked up something that's letting them through my firewall.

Any tech solutions out there?

Thanks, Judy

Thank you so much. Now that I'm looking for them, I don't see them.

But, I'm using Firefox so I'll do a search for a tool that will block flash driven ads, download an add-on and install it.

I'll be back here if they show up after that.

Much thanks. Judy