I had exactly the same problem. A bad backlight, and a monitor with no service tag number (because it was bought by itself, and not as part of a dell system) I had to use the phone (800) 624-9896 - it took some time to navigate the menus, but once I got to a person they wanted my order number. Now, I still have the packing slip (It was in the original box, and I tend to keep original boxes for large, hard-to-pack things) so I gave them the order number, explained the troubleshooting steps I took