You may be tuned to an input with no component or device connected to it. If you're trying to view a connected component, press INPUT and select which device or input.
The channel may be blank. Try changing the channels.
If you are watching your VCR and it is connected with the coaxial cable to the ANT/CABLE/SATIN jack, tune the TV to channel 3 or 4 (whichever channel is selected on the 3/4 switch on the back of your VCR). Also make sure the TV/VCR button on the VCR is in the correct mode (press the TV/VCR button on your VCR).