Our lounge pc is being operated on Windows 7 and compare to its previous Vista Home Premium, it is way far faster and more manifested so we are happy with that OS. Although Windows 7 supports most modern video and audio codecs and container formats out of the box, when it comes to play mkv files, WMP does not support it and when we installed pure codec with KMP on that HTPC, Windows Media Center played up again as Vista.
Hence we did googling as usual ( how can we survive in this cyber territory without this awesome search engine? no idea!) and downloaded Divx Plus 8 package to get the Divx Labs MKV splitter.
However the codec was good for only video not audio so we installed untested codec that my friend had downloaded before and WMC is now working good at the moment.