How to Play FLV (Flash Video) Files in Windows Media Player?
By default Windows Media Player (WMP) will not play flv and report that it does not have the correct codecs to play it.
There are two options (either of these two will work)
1) Downloading codecs package such as K-Lite . K-Lite is a tremendous codecs package that supports for various file formats such as 3gp, mp4 etc. Almost any movie format that you can think of or find on the internet, K-Lite will have a codec to play it. Installing the package will enable Windows Media Player to decode and play the file.
K-lite can be downloaded from here
2) Download a simple FLV plugin for Windows Media Player with no extra bells and whistles. The plugin is very lightweight and does exactly what it says - Plays FLV files and nothing extra.
PlayFLV plugin can be downloaded from here