Today, we started having problems with what I think is a set-top box issue. The TV plays videos over Netflix through our Wii so it is not a TV hardware issue. First, we were getting audio only and no video now we get no signal from the FioS external input. I have checked all of the cables and powered on/off all equipment. I have to believe this is a set top box issue. Any ideas on what to do next?
Are you using HDMI from the STB to TV? Low quality HDMI cables can cause the problem you described. Based on the checks you've done, a faulty cable is the thing that comes to mind.
Try replacing the cable. If that doesn't fix it, request a replacement STB.