Sounds like it could either be a power board or main board issue. If you're confident in opening up your TV, replacing either boards is pretty straight forward. Just be careful unplugging any wires/ribbons. For vizio parts, you can try Vizparts
Sounds like your network settings might've messed up. Is the co-star still in warranty? If so, I'd get a replacement from Vizio. If not, you can try Vizparts.com. They deal mainly with Vizio TVs and accessories.
Check that the cables are connected to the output ports of the source and also connected to the input source of the TV. If that is connected properly, next make sure the 'input' of the TV is selected to your output source (bluray, component, AV, etc.). If you're still not getting a signal, see if a factory reset will fix it. Worse case scenario, you might have a defective main board and need to replace it.