I have a 5 yr old Plasma by Panasonic. I had the same issue and spoke to a tv repairman. He informed me that a new circuit board would cost around $175 and a new Panasonic Plasma would be $400 so it wasn't worth getting a new circuit board. I was able to use a "band aid" solution below that seems to be working for now. I'm probably going to have to purchase a new tv within the next 2 years.
Try the following:
Unplug the TV for 1 minute and plug into a different power circuit, if possible, separate from the other components. Turn it on and it should work.
Try taking out the back cover and use a compressed air cleaner to clean all of the dust off the board.
Avoid powering off your tv and quickly turning it back on. The blinking light issue will surely occur.