Simple DVD Burner Question

[Lestat]

First, I know almost nothing about computers. I do know that I have a CD player in my computer that I can also write files to. But this cannot play a DVD movie disc (even though my computer itself seems perfectly capbable of playing a movie).

I am told that in order to stick in a Seinfeld CD and watch it on my computer, I need to purchase and install a DVD player for that. I am also told this is better because when I back up files a DVD will hold more info than a CD. Is this true?

Would anyone have any recommendations of what kind of DVD to buy and where to buy it? How much should I spend? Should I get one online, or just go to a CompUSA? I'd really appreciate any info. Thanks.