It is not overly difficult to open a Wii case.But you have to keep track of all the parts and screws you remove and take your time.Don't forget your remove steps.There are some stuff you have to prepare:Phillips screwdriver,tri-wing screwdriver,plastic bags to keep track of all the screws.you can purchase Wii repair parts in the repair part stock.
1.First,remove the screws on the right side of the Wii.Removing the screw under the two screws will allow you to slide out a plastic tray with a battery in it.There is another screw that you have to remove under that panel.
2.Remove four screws on the faceplate side.Slide the faceplate off the Wii.it is connected to the motherboard with a couple of thin wires so watch out.Disconnect the faceplate from the motherboard.
3.Remove those three screws on the left side of the Wii.Remove the two doors that cover the left side.If you pull on them they pop right out.
4.Remove the black piece that covers the left side,and a few screws to remove.
5.Now,Take the top half of the case off carefully,You are done.