Welcome to our forum, ranger!
I have a similar setup, only I have the line-level outputs of my receiver going into the line input of my sound card. That way, anything that plays on the receiver can be recorded on the PC.... AM-FM, TV, DVD, VHS, Casettes, Phono records, reel-to-reel tapes.
I use
Total Recorder to capture the audio to .mp3 files. It can even be scheduled to record when I'm away. I'm not familiar with WMP as I don't care much for it, and I was unaware that it had the capability to record an input.