I just bought a new Panasonic VIERA TC-P50GT30 50 inch.. I set up the stand, plugged it in... and nothing. It won't turn on?

Make sure there's power to the outlet and that the power cord is secured to the back of the TV. Those Panasonic TVs need the power cord to be pushed in pretty tight. You'll hear those clips snap into place.

If everything seems fine, then you'll probably want to exchange it since you just got it.