If there are DVDs that, because of their specific ratings, you don’t want to be played on your computer using Windows Media Player, you can block them from being played based on their rating. Note, however, that the blocking can be overridden by providing Administrative permission from the User Account Control.
"Authorizing Administrative Actions" for information about using and enabling the User Account Control if it isn’t enabled.
"Restricting Access to Web Content" for information about setting up and enabling parental controls.
"Restricting Content in Windows Media Center" for information about setting access restrictions on playing DVDs and other movies in Media Center.