When you started off I thought you meant physical DVD disks. Of course OSX has its own dvd player. For downloaded movies might I suggest 2 things. First get VLC which is free & has in-built codecs & understands all the newest video formats but sometimes can't play some wmv & ALso go to QuickTime's Preferences, ... see this: http://www.gnutellaforums.com/showth...threadid=34705 & also this: http://www.gnutellaforums.com/showth...threadid=34051