Is It Ok to Download and Burn an Xbox 360 Game for a Backup?

my modern warfare 2 wont work, when i press "PLAY GAME" it shows the opening screen then it says "the disc is unreadable" i just want to burn the game so i can install it to my hard drive and play with the original disc. is it ok to do this?

Suggestion:

Why not just rent or borrow the game and install that one, rather than having to resort to illegally downloading games? Besides, you would still have to mod your system to read the downloaded version as a game.