Ditto on the exchange. If it's new and you already have issues, better exchange it (I believe in the first few days they can't repair it, they have to replace it with a new unit).
But for the sake of sanity and peace of mind (to see if your LCD panel is dead or not), turn off the device, then turn it on by holding the power button, the home button, and the volume up keys (press and hold together) until the device powers ON and displays the recovery console. If you can see this image, your hardware is not dead and it's a software issue (from the recovery menu you can factory reset the tablet and that might clear the issue). But if this doesn't turn the LCD on, then it's dead. It's a hardware issue and you need to get it replaced.