Sometimes these things simply die like this. Go over the basics, including that the outlet has power, the set is plugged in, and the surge strip is turned on.
Is there any blinking light or anything that could be a diagnostics code?
If all of the simple stuff is right then you likely have a bad power board or other component inside the TV. You can take it to a TV repair shop if it is a higher end (> $1000) tv, otherwise it will likely be cheaper to just buy another one unfortunately.