You are probably on an input setting (HDMI, RCA, Component-1, etc.) that is not connected to an outside source. You need to change your input on your remote.
You need to change the input method for your TV. Try selecting a different input method with your remote control. Make sure that it is one which currently has a connected device. (such as a cable set top box, video game console, etc. )
It's quite possible that your connections are poor, check all necessary cables and inspect them for damage before reconnecting. Also be certain they are all correct.
