it's been my understanding that WMP will put DRM on the personal music files that you rip from your own cd's, meaning that it will license your pc to play the music but if you attempt to play the tunes on another pc they won't have the proper license to play
I've moved between several PC's, and even played my music on several different types of players: a Patriot Box Office media player that's hooked up to my TV, my Plex Media Server, all of my different kinds of MP3 players I've used (SanDisk, Zune, my Android devices), and I've never had an issue with them.
Plus, I never said I rip music with WMP . I did with my library ages ago to digitize it...but haven't ripped a CD in a while. I believe I still have used WMP to do it though and didn't notice any DRM injected into it.