Windows 7 MCE h264 in MKV Container Playback

I just installed Windows 7 x64 Pro and I cannot get my h264 in mkv container files to playback in Windows Media Center.

Also, when I use Media Player Classic on this platform to playback these files, it plays most of them, but the ones with DTS tracks, the video and audio continually cuts in and out every second and my audio video reciever goes to DTS mode and out during those cuts.

I heard all I need to do is load Haali Media Splitter to fix this. Is that it?

I also heard I need to download the Divx Tech Preview plugin, to get mkv playback, but I already get that using Media Player Classic. But should I do that too or only this?

I'm confused.