If you are using a cable or satellite set-top box as the source device for your TV, it is important to ensure that it has been properly turned on and connected to an active station.  If this is not done correctly, then your TV may display a blue screen with no picture. This could be due to the fact that the source device has not been set to the proper mode. To prevent this from happening, make sure that all of your connections are secure and that you have selected an appropriate station before turning on your television.  Additionally, if you experience any difficulties with connecting or setting up your devices, consult the user's manual for further instructions.