There is a dvd key programmed on your xbox you need to program in the dvd drive. You need the right kind of equipment to do so. You cant just plug it in.

just replaced the drive on my jtag, plus i do repairs for gaming systems locally, so i have dealt with hundreds of xboxs.

1. download flash 360 for your jtag, and put it on your hard drive, usb, whatever
2. Open it up on your jtag or rgh, and dump your original hand onto usb.
3. Plug new drive into your computer and use jungle flasher to find DVD key... take a picture or write it down, accurately.
4. Plug usb into the computer and make a copy of your original nand as a backup.
5. Download 360 flash tool for your computer.
6. Get xbox cpu key.. can be found in xell. if you don't know how then google
7. Open 360 flash tool, open your nand file and put in your cpu key.
8. Change dvd key in 360 flash tool, and save the file to your usb
9. Go back to your xbox, open up flash 360, and write the new nand just created to the xbox.
10. Use the new drive.

This is a very good method if you don't want to spoof drives or flash.. its what i used because my drive pcb was completely fried. luckily it was on my jtag!!

good luck

like they said above you need to match the dvd keys from the drive and the console, you cant just plug and play

You could just replace the laser
This is what i did and mine worked