I would like to first say that backing up a DVD should only be used to backup DVD’s that you own in your physical possession that you have purchased through a legal means.  This is not intended to help further any illegal causes, only to assist those with a legitimate use for backing up their DVD’s. 

This will walk you through the process step-by-step. 

Step #1.  First, you need to make sure your computer has the appropriate hardware to copy the DVD.  You need at least one DVD-RW drive in your computer, while a DVD-ROM drive is necessary to read the disc a DVD-RW drive is necessary to actually make the duplicate disc. 

Step #2.  Gather the necessary software.  I personally use DVDFab Decypter to decrypt the disc.  Then I use Roxio Easy DVD Copy 7 to actually burn the disc.  Roxio costs approximately $40-$60 depending upon your software source.  DVDFab Decrypter is available for free online. 

Step #3.  Select the disc you want to copy.  Insert the disc into the DVD-ROM or DVD-RW drive.  Open DVDFab Decrypter and once the program loads you should see a screen that on the left says DVD to DVD, under it you should have five options.  Full Disc, Main Movie, Split, Customize, and Clone.  I always select Full Disc for my copies.  On the right side of the screen, you should see Source and Target.  You want to select the drive that the movie is in as your source.  For your target, you want to name a folder on your hard drive that will contain the entire movie.  Please note: You must have approximately 17 gig of space on the high side to work with the movie file.  Most movies would not require that much space, however always best to have extra instead of not enough.  Once your source and target is selected click Start.  I am currently using DVDFab Decrypter version 4.0.5.0 the Free Edition it can be obtained from http://www.dvdidle.com/free.htm  .

Step #4.  Once the movie is done decrypting you, need to close DVDFab Decrypter, then open Roxio Easy DVD Copier.  Once the program is open, click on the Disc Image/ or DVD-Video Folder on the left.  That will move the bubble so that the option is selected.  Then click on select next to Disc Image/ DVD-Video Folder, follow the explorer to the folder in which you placed the movie file when you decrypted it using DVDFab Decrypter.  On the right side of the screen, click the bubble next to Recorder.  Select the DVD-RW drive in which you have inserted a blank DVD-R disc.  It is possible to burn onto either DVD-R or DVD+R, I however prefer DVD-R it is more versatile and works on more DVD players, especially the cheaper models that I have due to two small kids with no respect for electronics.  After you click on burn, the program will change to another screen that says Transcoding, what this means is that Roxio is taking all of the material and shrinking it so that it will fit into the disc space available on a standard blank DVD.  Roxio will select the appropriate burn speed based upon, the blank media and the capable speed of the DVD-RW drive that you are using.