Hi, I'm Nathan.Sorry to hear that you're having trouble, but I'll do my best to help you. Please give me a few moments to review your details here.
Can you tell me what is connected to the tv currently?Antenna, cable/satellite, etc?
Okay and you mentioned AV cables, do you mean red/white/yellow? Or hdmi?
Okay so can you press the INPUT button on the insignia remote, repeatedly, until you get to the AV (video) mode, does that show anything? What about on the hdmi1 input?
That points more to a problem with the box,
can you unplug power to the box for 60+ seconds to reboot it, then test again.
If no change, we need to test something else with the insignia, like a dvd player for example.