K-Lite Codec pack. Plays Nearly everything on the planet. Includes ffdshow. Noticed a few files out there that require this new x264 codec. Right Click and find out what codec is needed to play the file.

While back I was haveing problems with some files. Had the right codec but a newer version of it or sumthin like that. Little Program called Nic's four CC changer allowed me to get the files to play. (comes with K-lite)

Hope this helps.