DVI and Dual screen question

Hello all :)

Im new here and a new owner of a Alienware Area 51 ALX (pretty happy about it, saved up for a good while to afford it)

But....

have a couple of questions.

Now i could be mistaken or stupid, both are quiet possible, but i purchased the dual Nvidia 480 GTX for my gaming needs, should not come with four DVI slots and not two?

Secondly, I have also bought the Alienware 3d capable monitor and also have a quiet good 23inch Dell flat screen one.

I have connected both to the two DVI slots that i have, and am able to select dual screen, extended display, etc.

My question is, why cant I, or is it possible to play a dvd on one screen while playing a game on another?

Thanks for your time :)