New version of K-Lite Codec Pack available, have a try of the Mega Codec Pack, incredibly easy to install (v1.33)! I posted about this Codec Pack last month.

K-Lite Codec Pack is a collection of codecs and related tools. Codec is short for Compressor-decompressor. Codecs are needed for encoding and decoding (playing) audio and video. The K-Lite Codec Pack is designed as a user-friendly solution for playing all your movie files. With the K-Lite Codec Pack you should be able to play 99% of all the movies that you download from the internet.