take it to a game store and they'll fix it for 2 pounds or whatever in dollars

ok follow these steps
1. Take your disc put it in the xbox while its reading
2. Take your controller and then
3. Lightly tap on it where the disc drive is.
4. Then it should read
Could take a while to work and also if you are tapping to lightly try harder. I do not believe you should do this with the new xbox and if your xbox is newer and im not responsible for any damage done to your xbox and also it only works for so long.

-Shiizz- wrote so i turned on my xbox and when i tried to play mw3 it says open tray the disk aint scratched tho any help???

I Have Had This Problem Before, I Might Think You Need A New Lazer For It

Mine Blew!

Just try turning your Xbox off and back on or open and close the disc tray.