I consider that WMP is broken. It just wasn't made to appeal to wide-spread use across all the video/audio out there. Thus outside codecs have to be brought into the mix. While that generally works well, sometimes it doesn't -OR- past updates or installs for mass appeal has finally broken WMP. WMP by its own nature is restrive and can fall down all too easily. If possible try to totally remove it and re-stall again. -OR- upgrade to the next level of WMP if possible like from WMP 9 to 10, etc.. IMHO, I've moved on to other players like VLC or whatever works.
I had some .mkv files with dual audio, so I downloaded the latest K-Lite codec pack. It fixed the audio problem, but now when I play it on WMP, only half of the video is available. For example, a 45-minute video will play just fine for the first 22 min. or so, and then stop abruptly. The Now Play window would also display the clip as 22:30 long instead of 45:00. Does anyone know how to fix this so that WMP will play each video in its entirety? Any help is appreciated. Thank you!!