You got me this time
You can try one of the CODEC packs:
http://www.free-codecs.com/download/K_Lite_Codec_Pack.htm
http://www.free-codecs.com/download/Nimo_Codec_Pack.htm
http://www.free-codecs.com/download/Codec_Pack_All_in_1.htm
http://www.free-codecs.com/download/XP_Codec_Pack.htm
Good luck.