Xbox says disc is unreadable

Either the game no longer works and to buy a new one or you need to replace your dvd drive.

Clean the xbox 360 with a laser lens cleaning kit like this one:
http://www.gamestop.com/xbox-360/accessories/xbox-360-cleandr-laser-lens-cleaner/93068

your game is not right downloaded because probably is a piece of the game but i think is not the full game so try to download it somewhere other website and try it again.I hope it helps

maybe youve got to much memory!

i had this problem with my xbox and its due to either the laser or the magnet within the disc drive that holds the disc in place. the magnet may have come loose which mean u can either open the drive up to try and reposition it, or replace the drive all together. my suggestion would be to send the xbox to microsoft if under warranty or send it to a third party company to see if they can fix it. buying a new drive for your xbox involves some very complex firmware flashing which is not advised

I had the same problem but i sent it in. They said it was the eye reader error. Or the thing that reads the disc. Try buying a brand new game and try playing it. Alot of times when i have disc read errors i put the disc in where the xbox 360 part at the top goes in facing the xbox. Try that to see if it helps.

the problem is the disc drive.
you have to open it up and put some stick foam " like a sticky strip of foam, insulator : on top of the drive .
the problem is that the disc touches the laser assembly while turning cheating a ring on the disc.
i can fix your games as well as the disc drive if you feel like is to complicated.

This is a known issue with the 360, most likely the cause is that the spindle that holds the disc is loose or completely broken off. As the way the cap for the spindle was made, microsoft used a magnet to hold it in place instead of glue or soldering as most drives would have. This is just another instance of inferior workmanship on their part to save money.

Contact 1-800-4MY-XBOX to get an RMA issued.

THE SAME THING HAPPENED TO MINE I SENT IT TO MICROSOFT AND THEY FIXED THE PROBLEM. IT USUALLY IS THE DISC LASER THE READS THE DISC.

theres a known problem with the hitashi dvd drive in the xbox 360.
the only solution to this is a home repair job, look up on youtube on how to do this, although this isnt recommended as it voids warranty.
so the best way is definitely just to ring microsoft and send ur console in for repair.