Windows 7: Media Center & mkv files

Background: finaly getting around to taking advantage of Media Center.
Found out how to get vob files to play by letting MC see them as movies not just video. That part seems retarded, but still cannot get mkv files to play. I am using Sharks Codec pack - recomended settings - and mkv files play great with Media Player. Media Center, sees them as far as the "box", but says they are not there.
The goal is to remote up and use MC, then comes the new 5770/5750 and 3rd. monitor/screen. Work out ther media kinks first.

Do you have UAC turned off?
If so, please uninstall the Shark007 codecs until such time that you decide to enable UAC.

UAC must be active while installing my codecs,
and it must be active when making changes through the included settings applications.

EDIT, did you install the x64 Components addon?

UAC is on, Installed as administrator etc. Did not do the x64 add on.
This is what I have. img

I suggest you uninstall that version (its quite old) from the Help TAB of the Settings Appliication and install a current release.
The x64 Components are required for playback in Media Center.
Once the new version(s) are installed, browse your MKV files to get thumbnails.
After they are thumbed, open the settings application(s) and set the suggested settings.
For MKV playback on the xbox360, the Microsoft decoder must be selected on the H264 TAB.

Ok I'll upgrade and give that a shot when I get home tonight.
It seems odd, I mean mkv's play fine using current codec's in media-player, but not in center.

All seems well!
Thanks Shark007!!
Extreme appriciation & Rep.