Apple TV Not Connecting to WiFi

In mid-May I bundled Prism TV and Internet. I don't know if that relates to anything, but I mention it just in case. My iPhone, iPad, iMac, MacBook Pro and Apple TV all worked perfectly before and after that change.

A few days ago, my Apple TV (second generation) will no longer connect to my WiFi. All my other electronics are still working perfectly with WiFi.

I visited the Apple Store yesterday, and my Apple TV works well with their TV. They also upgraded my Apple TV to the most current version, and it still worked in the Apple Store.

Still no go at home. I have a five-bar signal from my WiFi but still cannot connect.

I've restarted my Apple Express and my Prism modem. The Centurylink tech set up a second network on the Prism router. No deal. It still won't connect.

All my settings and password checkout. I also bought a Micro USB and restored the Apple TV through iTunes and iMac hookup. Still won't work.

This is driving me nuts! I want to know why