Depends on the DVD. If it's one that you bought, then yes, you'll need some bits of software in order to bypass the protection and be able to rip the file onto your computer.
THere's a lot you have to buy, but if you only want to use it at this point in time, I like this one
http://magicdvdripper.com/I think that one removes the protection, but if not, ask around for a program that'll do that.