How do I create a file on a DVD-R/DVD+R disk that I can download onto my computer?

I have an old GO VIDEO DVD recorder and it allows me to record og 8mm and VHS tapes onto a DVD disk (either DVD-R, DVD+R, DVD-RW, or DVD+RW) but my computer doesn't recognize the file when I try to download it. I would like to edit the file with an editing software (I have Nero). Is there some step that I am missing to convert the og file to a digital file? DVD recorder doesn't allow me to save the file in any format such as MPeg, AVI, WMA, etc. Any help would be GREATLY appreciated.