You say when you close the tray, empty or not, the light blinks green. Can you hear the drive attempt to spin up (with an empty tray) or the disc spin up to the maximum RPMs? If it does attempt to spin up with no disc but it doesn't spin up with a CD, then something is failing, possibly the laser head assembly. If the drive DOES spin up, then the problem lies elsewhere. BTW (by the way), how long have you used the drive, what kind of usage/load did you put on it (lot of reading/burning, small amount, etc.), and when did this begin?
The more info you can supply about how you used it, the more you can get help/advice. From one "noob" to another, we are here to help.