Mine did the same thing, but I after it shut down, I could start it back up. I replaced the power supply brick and it was fine.
If you want, you can try taking it apart and cleaning out the dust.
IFIXIT is a good website that shows you step by step how to take it apart. The hardest part is taking out the rubber feet. You need an awl or a small eye glasses screw driver to poke the center and pry them out.
Panasonic 50" Plasma 3D Smart TV
HTPC/Gaming PC (i7 860, SSD, GTX 660 Ti+), Xbox One, Xbox 360, Wii-U, Wii, N64, NES
Nokia Lumia 928 W10M