Our Vizio TV was on, then went black and started making a buzzing sound. We turned the TV off and then turned in back on, but received no response from the system. The Visio LED power light truns from amber to white, and the screen appears to flash, but the menu won't appear (no display at all), there is no further activity from the screen and we are unable to power the system off using the power button. Does this sound familiar to anyone?