First off I would suggest you do a Google Search to get an understanding of what Codec's are and what function they perform. K-lite Codec Paks, and CCCP are probably some of the best, but it may depend on your OS.

Just keep in mind that using more than 1 Codec Pak will cause Problems.

There is a MS WMP Codec Pak included in Link Below.

See here for suggestions By LOTR. Hope this Helps.

CODECs list for Movies/Audio/ Alternate players / Video help forums/ video-mp3 fixers
Hope this Helps.

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