If the room your GC is in dusty or smokey, then the laser that reads the disc can get clouded, and therefore won't work properly. Make sure your Cube isn't stored on carpet (the ventilation can suck in dust) and it has enough room for the ventilation to work properly. When mine was bad, I used a reverse function on a vacuum cleaner to to gently blow into the ventilation area (blowing with your mouth will release small saliva droplets), and it's worked fine ever since. Hope it helps.