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Want to update this 2020 , I have had the same problem and it's one thing that can cause these not working A,B,Y , touchscreen analogues and the D pad , I have had this problem on my partner's Wii u that I got her for Christmas , not sure if something has been dropped on it but here's what's wrong with your Wii u , if you have a screen saver take it off like what Lucas has said , if that has not worked look and examine your screen with a touch putting it left to right looking and the screen from every angle this is to make sure there is nothing trapped in the small gaps the screen has to the case , most likely you have something stuck in the gap if not there is a dent or deep scratch in your screen , if this has happened to you (The A is to accept something and the B is to go back this can not happen if you had your finger or pen on the screen because the console is processing it though the touchpad not the buttons There for if these buttons are not working but some are, its cause your screen has pressure so the console thinks your pressing it all the time