You can't just copy an audio CD to your hard drive as files, unless you have an older Plextor CD ROM drive (it came with software to make music CDA files look like, and behave like .wav files directly from the CD).
You need a program that "rips" the CDA files into a form the computer can manage, like Winamp, or lots of others out there that do this process very well.
All files copied directly from a CD are marked 'read only' to prevent novice computer users from trying to write to an unwritable media. The converted files made by a program that rips the music files will not likely make the new file generated read-only.