Maybe if you give us the model number we can take a look. But basically you would want to do some googling to see if you can find more setting for the unit.
Can you hear the DVD spin when you insert a DVD? If you can, then there might be a chance that the laser's lens has some crude on it. You would have to do some disassembly to get to it, but if you do just very gently clean it with a q-tip and some isopropyl alcohol.