How did you burn it with Nero? If you simply made a data DVD and burnt the ISO file to, then it won't work as a bootable DVD.
You need to choose the "Burn Image" and select the ISO file. The procedure varies depending on the version of Nero you are running.
Alternatively, you could make a "Virtual DVD" drive using Daemon Tools, mount the ISO image, and then use Nero to do a DVD-to-DVD copy using the virtual drive as the source and your DVD burner as the destination.