Chienworks is right - it doesn't matter where the music started from, be it a CD or a download. It does have to end up on the HD though - you can't use music direct from the CD.
Actually one can use WMA, WAV, MP3, etc. files direct from a data CD. You'll have to make sure that CD is in your drive the whole time you are editing and rendering. Audio CDs must be ripped to a data format before being used. However, since the original poster mentioned WMA files i was pretty sure it wasn't an audio CD being used at editing time.