sounds like an issue with Asus board overheating or just a bad board VRM. I play All my content through WMC, just save the HD files to a .MKV and windows will hanlde it with just the codec.
I didn't like the .m2ts format because of all the extra software required to play them. The biggest issue is the lack of "uninstall" most software companies are going to. One example is cyberlink. Installs 9 programs in control panel to remove one at a time if you decide to get rid of it.
Well prior to buying this HTPC, I was using a dedicated media player on my network, so it would play any type of media file, no need to download anything. Since then, I decided to go with the HTPC, so I wasn't going to go through 4.5TB of media and re-encode all my files but in XBMC, there is no need to download 3rd party codecs............as they're all built into XBMC..it did play, but not for very long, or with the GPU, the HTPC just shut down on me after a short time. I'm not a big fan of WMC or any other Windows related software but I'm going to look into other media software for playback that I've seen lately if/when I get my HTPC back from the vendor. I know they tested my build before shipping it out, so I'll find out soon enough what the problem is.