I'm not sure whether it would solve your problem or not but, in any case, you might want to consider switching from K-lite (I used it for years, btw) to Shark007's Win7 Codecs
. (Free, like K-lite, of course.) He keeps them updated like K-lite does and includes everything you might need but what sets his packs apart, imo, are the x86 and x64 settings applications he includes that allow you to more easily tweak what splitters and filters get used for which file types and easily make configuration changes. And they work well with WMC and WMP (although I use other players myself which they also work fairly well with.) As a side effect, removing K-lite and installing his set and going through the settings application and tweaking as appropriate might solve your problem. Anyway, I highly recommend you check out his site at the link above and at least take a look.
Also you might want to look for info and or post about your issue in the "Music, Pictures and Video" thread on this site.