Need help please...

TV lamp is good. There are no messages or indicator lights that have come on to tell me the lamp is going out. Just recently all my inputs (cable, dvd, etc...) have a blank, black screen when selected. I can hear the audio but no screen.
The TV Guide, and menu screens work (I can see them) but when I select and option and return to the input device there is just the blank, black screen.
When I select a device that is not powered on I get the Blue "video mute screen". This is supposed to come on when the TV doesnt pick up a signal from the device.
So I know the TV is picking up a signal (from the powered on device).

Please Help...anyone...

Lets try initializing the set. with the set on and from the remote hit Menu-2-4-7-0 then from that menu simply hit enter, this resets the set

I could watch the TV. But two weeks ago, whenever I select the device(transition)button, the TV turns to blue(like no signal) for about 15 seconds, and then the light on the front panel(timer) started to blink for 30-45 seconds. it turns off completely. I also found the timer doesn't work. And have the same problem(turn off automatically).

I reset the TV, but it doesn't work.

Anyone who could help?

Thanks