How can you get the clips to make videos? And can you download them from a DVD?

I remember asking this already (but only one person answered, and she's not here anymore)

I want to make a youtube video, but I don't know how to get the clips. :/

Oh, and can you download videos from the DVD? (Mom will be SO angry if I buy it. XD)

(I know I already made a youtube video, but I can't use it anymore because a family member said it's the reason my laptop got a virus. HE STILL DOESN'T HAVE PROOF!)