Has this always happened, or is it a new thing? Have you changed your version of WMP?
Have you tried playing songs thru a different player? If so, does the same thing happen?

Try playing things thru VLC player...see if things are any different.
http://www.videolan.org/vlc/

And a bit of info to help with playing files through VLC
Using VLC player (Windows)

I don't use WMP so I've never seen this, maybe someone else on the forum who uses WMP regularly will have something more to add!!