R7000 Not Connecting to Internet

Thank you very much for all the suggestions. Well, my son was here during all this (he's an adult and lives a couple hours away) and I asked him last night if he had done anything new network wise to his laptop and he had recently loaded Expressvpn onto his laptop. He only connected to the Asus router via WiFi during his visit. I ran an ipconfig/all and found that the Netgear router had a new IP address. I browsed to it and expressvpn software came up asking my for the router's password which I entered. That gave me limited access to the router's config so I called Express. They said that my router had their firmware on it and they had a utility to reload the Netgear firmware which I did and all is well again. When I asked how this happened, they stated that I must have loaded it or it was on there when I bought it. Well I didn't load it, and my son doesn't have access to that router physically or network wise, and I bought it brand new from Best Buy 4 years ago. Quite the mystery to me.