Nintendo Wii U

It was working fine yesterday and has never done this. My gamepad is showing everything, HDMI is plugged into the tv and wii u, power block in and in Wii U. I looked it up other places and it says to change your resolution from your gamepad, and it said it unable to change resolution. Help????

I just purchased a wii u and I tried connecting it to the TV but It said no signal. My game pad connects to the wii u but says I should put in a pattern as shown on the TV but I cant see it!