While it's theoretically possible, there would be so many drawbacks to trying to create a CD on DVD and to play it back that there's no reason to do it. If you don't want to create a second DVD immediately, most programs like Nero & Roxio would allow you to back up the DVD image to a computer's or external hard drive, either in its original folder configuration, or as a single file (ISO image). Then if you need to you can burn that to DVD in the future. Since you have a DVD-R there should be no copy protection.