My xbox 360 games are unreadable or undetectable. help?

every time i put a game into my 360, it says its either unreadable or its undetectable. it used to take about 20 minutes to get it to work, but now it wont work at all, i've tried many different games, and i've emailed microsoft about it, but i dont want to risk it getting damaged in shipping. i've heard the laser could be burned out or mis-aligned, but i'm not sure how to fix it, if you can, or if i should even try it myself. help would be much appreciated.