Computer Woes Solved? Multi-browser, Multi-system Malware Stopped! [I Hope]

Me, until a couple of hours ago.

Noted here in the last couple of posts, I've been beset by computer woes since some time mid-weekend. Somehow, all of our devices were plagued by malware, weird ads and attempts to get us to install various software. Neither of us knows how it happened, but I seem to have sort of solved the problem. I think. It's too early for cartwheels.

But I'm going to explain in as detailed a way as I can, so that if you have a similar problem, you can try the same thing.

We were getting popups, over-sized browser windows with either a) legit looking ads, b) fake looking ads, c) alerts to either install or upgrade video players, plugins and whatnot, and d) actual attempts to install files, all you have to do is click "ok." Fortunately, both of us here are smart enough not to install anything, though the source of this problem remains a mystery. And that's not all. Clunky, ugly, blinking, 90s-style "scare" ads started showing up in areas of web pages that ordinarily hold Google AdSense-type ads. But the weirdest part is, this was all of the sudden happening on a Windows 8 PC, a Windows 7 PC, a MacBook Pro running Mavericks, and a Galaxy S4 phone running Android Kit Kat.  And on these devices, it was happening in Internet Explorer, Firefox, Chrome and Safari, variously. Weird, right?

Didn't matter what device or operating system.

I called Cox, our internet provider, because even though I'd run every malware and virus program I could think of, the devices themselves were insisting that they were clean. It must, I thought, be either the router or the modem. The first lady was nice as could be, but had no idea what my problem might be. The second tier of help was too smart for me, two or three notches ahead of my experience level (which isn't ordinarily too shabby). But she got me the solution that is holding at the moment:

Factory reset the wireless router. Rename the router. Change the password, and keep it complicated. Then, I restarted all of the devices, one-by-one got them onto the network with the new settings. Also, I opened the internet pages I knew to be experiencing phony ads. I then reloaded the pages holding the shift key in. Poof, the bad ads

Didn't matter what browser either, though it
affected different browsers on different
devices.

disappeared. For reals. So far, the popup ads seem to be gone as well. On all systems.

So, though I won't even pretend to understand where this came from or what was really going on, it's clear that this goofy malware was coming through the router and running clean, because no anti-virus or anti-malware software could even see it running. Doesn't this sound kind of new to you? I've certainly never heard of it.

EDITED TO ADD: The Cox tech lady also advised me to assign individual MAC addresses to individual devices, somthing that is both a little outside my experience level, AND, seems to me like it would be awkward when we have guests, or want to add devices. So, I'll reserve that trick for if this bizarre occurrence ever happens again.