Problems with new WiFi router

I'm using a NETGEAR N300 wifi router. Yesterday everything seemed fine, except for my wife's Ipad (but that's another issue).

On a laptop running Windows 10 Home.

Today I can get on my main IP site, at&t yahoo just fine (sort of), but I keep getting 404 error message everytime I try any site that isn't part of Yahoo.

I apologize for being cryptic, I'm having to post this using my phone.

Edit: I logged off of WiFi on my phone, and now the computer is letting me on TFP. I'm going to try some other sites.

 

Thanks! That's what I did earlier today. After much trial & error (and cussing) I finally got the router to recognize our devices, and we can now use the internet without the damned login & 404 error messages.

Now I just need to figure just how secure.....if at all.....our internet is.

Don't laugh. This is my first attempt at setting up a wireless router. Both the router & computer are used/new-to-me, which certainly steepened the learning curve .