I have a similar problem to MTOW's. Some of my music files appear in the "All Music" folder of Windows Media Player, but the majority, (mostly music I've put onto the hard drive direct from CDs using ITunes), are in the "Other Media" folder.
Can anyone tell me how to move them into the "All Music" folder or have them recognised by the program as music files? Media player won't allow them to be moved between folders.