It does sound like a software issue to me. Have you tried Windows Media Player Classic?
C:\Program Files\Windows Media Player\mplayer2.exe
I think it is related to whatever is decoding the mp3's. Either it is using the wrong decoder or it got all fuddled up somehow. You might try uninstalling any extra software you think might be causing an issue. Media Players, codec packs, etc...
- Hope some of this helps