Xbox 360 won't read disks?

I turn on my xbox and I am taken to the dashboard. I put a disk in the tray and close it. It says reading disk and makes a noise that sounds like the disk is spinning and it continues to say reading disk. It goes nowhere from there. I have tried turning the xbox vertically and horizontally. I think that the disk drive is busted and it isn't catching on the disk. I don't think that the lazer is busted. It works from time to time and once I get it working it works for as long it is on, but if I leave it off for longer than a half an hour or so it stops. Any suggestions besides buying a new xbox? By the way, I have an arade.