Heres the story.
My brother was playing one of our Wii games, Harry Potter 5, and the Wii suddenly froze. It wouldn't turn off so I was forced to unplug it. Then once I plugged it back in, I turned it back on, and it said the disc was unreadable. I took the disc and cleaning it off completely and put it back in. It read the disc, but a few seconds after I pressed the "start" button, it said there's an error and that the disc must be removed and the Wii must be restarted. I did this and the same thing happened. I then tryed 2 other games with the same result. And to go along with this, whenever I insert a disc, take one out, or turn the Wii on it makes a loud buzzing noise.
I was thinking about sending it in to Nintendo but I thought that may be too drastic.