Well for a start what drive is it?
POT tweak or replace it.
thanksWhat this guy said. ^^
Here is a good tutorial for how to POT tweak.
Your Drives DVD* KEY.If the drive is completely dead you can always order one online from here
But you will need to either know how to solder or dump your Drives CPU KEY and put it on the new one
in your case if only the laser is dead you can just by the laser, look around on that page for the right product that would fit your xbox or your drive