Given the price of DVD burners, you're best just getting a new one. You can get a Lite On or NEC for $30 or so. If you get an OEM you'll save a few $s but you won't get any burning software, e.g., Nero, and if you're using the program that came with your DVD burner, it won't likely work with the new one. Other than checking connections and updating firmware, which you likely won't be able to do if if it's not working, I don't think there's much you can do.
