Put ur finger in the disc tray and on the top part, theres a little thing , spin it, the tray will shut, open up put ur game back in and it should work

hope i helped

deshano9 wrote their is multiple ways to go with

started tapping the top of the xbox where the disk is then after a few goes it worked

This could scratch games. But a sure fix is either,

take ur xbox apart and on the drive take the disc drive cover off and on the back of it there are 2 little screws. then ur going to turn the one on the left screw left just a little then it will be fixed just ur game in and try it before u put ur xbox 360 back together.

Or Take apart your xbox, then the laser might be out of place you move it forward.

You just slam disk tray shut not to hard or to soft, rather than take it apart.

open and close your disk tray really fast.