Can I make a DVD backup copy of my downloaded product? If so, which files do I copy?
You can backup the installer, not the installed program. What downloaded product are you are trying to backup the installer of?
I just purchased Photoshop Elements 10. I downloaded the software but would feel more comfortable keeping a separate copy on DVD in case I need to re-install quickly in case of a computer problem which corrupts the hard drive installer.
You can backup by writing the downloaded files on the DVD.