Need codec for HD .wmv files

Hey guys-n-gals! I'm working on a PC (WinXP MCE SP2) and the owner has a BluRay bruner installed. We can play any videos we want using PowerDVD. This includes BluRay and the HD .wmv files. However, he has some files which (by default) want to open in Windows Media Player. These are the HD .wmv files. When WMP opens, it says "codec required" so I installed the KLite Mega Pack. This did NOT correct the lack of a codec. Because the PCs owner has absolutely NO idea on how to do even basic stuff on the PC, I'd rather not install a different media player unless absolutely necessary. If I can just get Windows Media Player to playback the HD .wmv files (and any other files) it would be ideal. I tried to set it up so that ALL video files would open in PowerDVD but in some cases this isn't practical or really desired. Any help with this subject will be GREATLY appreciated!!!

Thanks!

(I had originally posted a few days ago and got no answers to this thread and I have made a little progress since then, but the PC owner really has no idea what he's doing so he has the ability to undo the few things that I've done to help him)

 

Problem solved. I used the KLite Codec Tweak to check the status of the codecs and found that some hadn't fully installed correctly (or at all) so I uninstalled the codec pack, rebooted, reinstalled the codec pack and paid closer attention to which codecs were being installed, and it's all OK now. :-D