Xbox 360 Disc Read Error (Open Tray Problem) - Faulty Laser?

I have a disc read error that may have something to do with a faulty laser, or it may not... basically the laser is not moving back and forth properly, and makes a clicking noise (whilst vibrating slightly) when trying to read discs. It is the same with CDs, DVDs and all my games. I have tried all the solutions I have found on forums etc such as: Check ribbon cables for breakages (continuity tested - all fine) Check worm motor is running smoothly (seems to be ok) Adjust dashpot setting to increase laser power (currently set to 3KOhm) All I can think of now is that the laser is dying... Has anyone else had this problem and managed to solve it? I would appreciate any help I can get... Thanks