Instructions
Insert a blank writable audio CD into your computer's CD writer drive.
Launch your computer's CD writer utility if it does not load automatically.
Add the music you wish to copy from your computer to the Xbox into the CD writer utility's burn list. Select "Add" or "Import" from the utility's "File" menu or click the similarly named buttons near the burn list. Choose the music files or folders you wish to burn from the browser.
Click "Burn" or "Burn Disc" to write the music from your computer onto the blank writable audio CD. While you may use this disc for audio playback, it will serve as your conduit to the Xbox 360 hard drive. Eject the CD from your computer's CD writer drive when the burn completes.
Turn on the Xbox 360 console with its disc tray empty.
Open the Xbox 360's disc tray and insert the newly burned CD. Close the disc tray. The Xbox 360's music player will launch automatically.
Scroll to the "Rip CD" option.
Deselect any of the CD's tracks you do not wish to copy onto the Xbox 360's hard drive.
Scroll to "Rip CD" to begin copying the computer's music from the CD onto the Xbox 360 hard drive.