This means there's a hardware fault in the TV, nothing within normal operation will prevent the Polaroid welcome screen from showing up. This set needs repairs, and in most cases it's the power supply/backlight circuit that's failed.
However it's worth it to try a hard reset, as sometimes the processor in the TV can simply have locked up.
The first thing you would try, is disconnect the set from power, then press and hold the power button on the TV itself (not the remote), for 10 seconds and release. Then plug the set back in, and also check that the power cord is connected tight at the TV as well. Press power once, and see if the set powers up normally. Try this procedure up to 3 times.
If you still have the same problem, then the power inverter board needs to be replaced and this costs as much as it costs to replace the set. The TV is almost 8 years old which is about the most you can expect out of it. Further costs would be better spent on replacing the set. I'm sorry for the bad news.
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