Thanks for the reply.
Unfortunately, there isn't a fix for this that does not require opening the TV up, and if you're still within the one year Warranty, then I would suggest contacting Panasonic and having them repair it under Warranty.
The problem is that the power board, in the TV, is not powering up at all. The quick fix is that it could be simply that one of the Ceramic Fuses on this board is blown. To access the fuse, you will need to remove the screws on the rear of the TV and remove the entire rear panel.
The fuses will be located on the board where the power cord connects. Please do not visually inspect these, but rather use a DMM (multi-meter) to test across the fuse for continuity. If one or more is found blown, then replace with one of the same type and rating from your local Hardware store.
If the new fuse does not cure the problem then, there is a failure on the power supply board inside the TV. Commonly the capacitors on this board will receive a surge and then fail- in which case it would be more cost effective to replace the board itself.
If you're looking to make this repair yourself, then you can purchase the Power Supply Board for your set at the link below: