you cloud check if the laser is stuck at the end of its track.
You can try to reset the laser. If it is the regular drive, Open the drive, Unplug the power while the drive is out. Plug the power back in. And as the Xbox starts up, force the drive back into the xbox. Don't like break it forcing it in, but give it a little shove and you should hear the laser re-aligning.
Also, how to clean the laser, I always used those little CD Cleaner CDs with the little brushes on them. Otherwise, I mean you could open it up and clean it with a Q-Tip and some rubbing alcohol.
Oh, also, If it does what I first said, make like a little grinding noise, then say "Reading Disk" and then come up as no Disk in the tray, it is 'prolly the motor that went bad. Happened to my last one. You can always try the "Ghetto Tap" method. It actually worked for me for awhile until I got mine replaced.
What you do it, lay the Xbox on it's side, Like horizontally, Close the drive with the disk in it, and as soon as it closes, take your edge of the controller, and right above the CD tray, rapidly tap the xbox. Don't like beat it, but you can't be super soft with it either. Like moderate force. Sounds crazy, but it actually worked for me. Takes a few tries of ejecting and putting it back in, then tapping it again, but eventually you will see it will say "Reading Disk" for a slightly longer amount of time. And eventually it will work.
And by "Few tries" I mean like 15 minutes of messing with it.