Hi Frenchy,
Without knowing exactly how it was encoded you could be here all day downloading different codecs...
so why not try one of the programs on this page:
http://www.free-codecs.com/Software/...dentifiers.htm
Most are freeware and I'm sure you'll find exactly what you need. After you have found which codec was used, I'm sure the same site has the codec you need!
From painful personal experience I would stay away from installing codec packs!
Hope this helps :)