it sounds like the laser assembly in the optical drive needs replaced. Follow the instructions in the guide: Installing Nintendo Wii DVD Drive. You can get the tri wing screwdriver at nintendo screwdriver.com
It is tricky to do on a small screw, but you can use a drill bit that is slightly smaller than the head of the screw to separate the head from the screw shaft. You can then use a pair of pliers to remove the remaining threaded piece of the screw that remains in the threaded hole. Sorry, This is a little difficult to describe with just words. Maybe I'll Try to get a picture of what I'm talking about. Tri Wing Screwdrivers