I have a Vizio TV VX21L HDTV10A which has a problem with the control and the buttons in the TV. The power, channel up and down, volume and input button in the TV do not work correctly. Consequently I can not control the TV, or even power off the TV, unless I unplug the power. The problem comes when I press the power button and the channel goes up, and then I press the volume down and the channel goes down, and they are simply not working right. The control does not communicate with the TV at all. Can you help me identify the part of the TV that I need to change, where to find it, the cost and everything?