Then you need a good Codec pack. The K-Lite pack is the best one.
What is K-Lite Codec Pack ?
K-Lite Codec Pack is a collection of codecs and related tools. Codecs are required to encode and/or decode (play) audio and video. The K-Lite Codec Pack is designed as a user-friendly solution for playing all your movie files. Follow the simple steps of my previous article How To Play All Files In Window Media Player.