Hello fellow chess player, If you have problems playing the video on your PC or Mac I suggest you to download a Free VLC Video Player by following this link: http://www.videolan.org/vlc/index.html. It is available for Windows, iOS and Linux OS. If you have any questions you can always reach us here: www.thechessworld.com/help/contacts www.facebook.com/thechessworld Thanks for downloading our video course, and good luck with your chess. Yury Markushin and Team TheChessWorld.com