You can try cleaning the laser if you're careful and you know what you're doing. If neither of these qualities apply, then you can try a laser cleaning disc. Other than that, unless you're able (or willing) to attempt a repair yourself, it's time to buy a new one!
its not on the power supply, but probably it's on the motor and the laser.. try to clean the laser with a soft cotton but don't put any chem liquids just only water. but if nothing happens, buy DIsc cleaners in the market or consult a service center near you....