Hi there, My Vista x64 Media Center just won't play MKV files. Windows Media Player plays the files just fine (according to GraphStudio all the needed codecs are in place). I've made the registry changes so the MKV extension is known to Windows and a double-click on a MKV file plays the file perfectly in Media Player. In Media Center however I keep getting the error message 'Cannot play video. Windows Media Center cannot open the file.' when I try to play it through either MyMovies or the default video's section. Any idea's??? Thanks!