I have a Dell 15" flat panel. It's started turning off at start up & I need to turn it off & on 15 - 20 times then it stays on until I turn the monitor off. I'm frustrated as it doesn't turn off any other time except when it's turned back on or at the start up. Is it just old & needs replacing? That's what a computer geek told me. But if it's ready for the bone yard why doesn't it turn off at other times, too?
Since it does it cold, I'd put the blame on cracked solder connections that heat up and expand making a constant connection after the monitor warms up. It will only get worse with time. My suspicion is in the power supply area. If you are so inclined to take it apart, look at larger wires and pins closely on the bottom of the circuit board, (magnifying glass closely, those cracks are tiny). You may see hair-line cracks in the solder around the wire/pin, most likely at transformers or power transistors. You can re-solder them if you have a decent pencil-type soldering iron. Never use a soldering "gun" type, they get super-hot and have a tremendous magnetic field around the heating element that can electrically destroy circuits. Or you can just junk it and get a new one. I like LG monitors myself. Go big, go wide... think Blue-Ray.