There was a deleted post on here where someone was getting no response from the Wii but it was outputting a black screen with a white dot in the upper right. My guess was that it is a dead/loose bluetooth module, but I took two months to notice the post and only realized it was deleted after I was unable to comment (mods can see deleted posts). Regardless, I wanted to bring this Wii troubleshooting flowchart to people's attention.