DVD drive not readind discs

So I purchased a DVD drive off Ebay. An NEC ND-1100A DVD+R. No box, manuals, software. yeah yeah, maybe I'm stupid, but it was cheap and "Hey, I know how computers work. How hard could installing a DVD drive be?" Apparently very much so.

The computer recognizes the drive just fine, but it doesn't read any discs that are put into it. Mechanically all the parts are fine, the discs are spinning and what not. But it doesn't read them. I've tried black DVs and DVDs, as well as legit CDs and DVDs. I contacted NEC tech support, but they said the same thing their website said, which was exceddinly unhelpful. I tried updating the firmware to the newest version, but the program wouldn't acknowledge the drive. So I ask here for help.

1. I read that you can update the firmware through DOS. Can anyone tell me how I go about doing that, step by step? Or if you think that would even help. I'm running Windows XP.

2. Any other ideas on what I could do to get it to work? The drive shouldn't be defective, as this is the second one that I've recieved from the guy, and he tested it personally before he sent it out and said it was working. So I'm getting the impression that I'm doing something wrong.

Any help would be appreciated.

The obvious test is to try booting from a CD using the drive. Get one from www.ultimatebootcd.com, or a Linux live CD or something, or even just use your Windows installation disc. If it can read a disc to boot from, then at least you'll know the hardware is working.

If this proves the hardware is not working, try a different cable. I'm willing to bet that if the drive came without accessories you used the same ribbon cable on both drives you tried, and if there's a fault in the cable then both drives would appear to be broken. After that, try plugging the drive into the primary IDE connector on your motherboard (disconnect the hard drive(s) temporarily; it won't matter if you're using a bootable CD to test) - there could be a fault on your secondary controller.

Firmware flashing should be a last resort.