If you are trying to play a DVD on your Windows PC and can not, try this software:  http://www.videolan.org/vlc/index.html

If you want to convert a DVD into a digital file that can saved on a USB key or a computer and easily shared and viewed, it must be converted into a format such as MPEG or AVI.  This is also helpful if you want to convert to view on an iPad or iPhone.  Download this software and convert the DVD using this software: http://www.freemake.com/download?id=FreemakeVideoConverter.exe