If your TV is not displaying properly, there can be myriad problems that could exist. It could be a very simple issue to solve, or it could be more complex and require professional service. To diagnose your issue and narrow down the problem, follow these steps.
Turn on your TV. If it does not turn on at all, check the power cable and ensure that it is plugged in all the way. Also, check the outlet to ensure that the outlet is working. Try a different outlet to see if that will work. If you know the outlet works and your TV still does not turn on, then you may have a faulty power supply.
Plug in an external device, such as a DVD player, cable box or video game console. Make sure you are on the correct video input. If it is not displaying, check the video connections. If possible, try a different video connection. For example, if you connect your DVD player via HDMI and it does not work, try using a yellow, white and red composite cable. You could have a faulty video input. Also, check your devices on other TVs to ensure that they are in working condition.
Check the bulb. If your TV turns on but nothing displays and you are using an LCD projection or DLP TV, the bulb might have gone out and needs to be replaced. Consult your manual to determine where the bulb is located. You should be able to order a replacement bulb and install it yourself.
Check the video settings. If your colours are off or the picture is blurry, you can adjust them to the proper settings in your TV's video menu. There should be presets that give you the best picture for sports, news, movies, etc., or you can adjust them yourself for the best picture.