Hi Anderson, since it appear you are new, I'll give you some advise. First, these forums have tons of information on this. This question has been asked, so using the search feaure above is definitely your friend.
However, we all start somewhere. In short, no, you can not change the factory NAV system to play DVDs. It simply does not have a DVD player for that purpose. The NAV DVD goes in a special slot so that the NAV works, but that player is only for the NAV DISC and will not play movies.