It most assuredly cannot alter the original DVD if it is a retail DVD bought from a store. DVD is a read only format so, besides dragging your keys across the disk, it is impossible to alter the disk in any way. Recordable DVDs can be altered, but that's another story. And in any case, the so-called "ripping" of audio, video or whatever is basically just a fancy way of saying it copies the data from the shiny disk onto your hard disk, leaving the original as it was. So feel free to rip away with impunity. But be sure to watch out for the RIAA and MPAA who are spying on you and prepared to send storm troopers crashing through your windows as soon as you hit the copy button!