Playing H.264 files on Windows Media PLayer 11 on Vista

I am not sure if this is the right forum for this question.

I would like to play a H.264 video file on Vista. I have installed PowerDVD 7.0 on the system. In XP, Windows Media PLayer 10 uses the PowerDVD to play the video file. On Vista Windows Media PLayer 11 shows an error message that the correct codec is not found, but still plays the video. But it does not seem to be using DirectX as I am not able to create a graph using Graphedit. I want to be able to play the H.264 through DirectX on Vista. Or is there any other way to do this

Thanks,

CACUSer