My sanyo 42 inch plasma has a blue screen, i can hear the sound on the tv but screen remains blue. can u help please

Be sure your channel settings are correct and that you have proper orientation of the hook up cables. See if your remote has a video-mute if so turn it off...a video-mute will produce a blue or black screen. To be sure its not the tuner that's enter the menu screen if you can see the menu then the tuner is ok this means the down-stream video is functioning. Be sure to have all your input devices set to the correct output ports. If all check good and still blue screen then the logic section is not processing video codecs and needs servicing.