If it's accepting the disc and you can hear it spinning up but it's not reading the disc and displaying the fault code then it could be just that the laser lens needs a clean. Disconnect the mains
then take off the top and find the laser lens, dip a cotten bud in meths and lightly twist it over the surface of the lens, then repeat with a dry cotton bud. If that works it was just dust on the lens breaking up the beam, if not laser will have gone low emission and need changing, laser will probably be £40 and the labour around the same so cheaper to buy a new unit, which is the reason I got out the electrical trade 5 years ago
Darren