I really hate to suggest this since it doesn't solve the problem but... I'd advise using something other than WMP. Winamp Pro is now free and is an excellent "do-all" music player (I don't use the video player aspect of it), as is Foobar2K. VLC and Media Player Classic are excellent "do-all" media/video players. I've never had a problem with either and I use those programs because I have file formats that WMP won't play.
As for Blu-Ray playback, there's no free options except as mentioned, but I'm pretty sure you can find a free tool to rip it (Handbrake?) if you so desire.
I found a work around in a windows forum where I use this program to copy then convert it so I can watch it, but I don't want to have to go through all that.
I have Foobar and VLC, they're nice but missing somethings I find useful in WMP. WMP hasn't let me down yet as any file I find that doesn't work in WMP I can usually find codecs for. I have had issues with a corrupt library but was able to fix it via the windows forums. I've tried many other media players out there over the years but I keep going back to WMP, mostly because of familiarity, partially because it has more continuous and steady support than anything else.
I'll let you all know if anything works. If not, how do I uninstall WMP then re-install it?