Can you access the files in any other way, eg using your preferred media player or any other player?
Try connecting the drive to another USB port on the computer.
Have you backed these files up elsewhere? If not, I would try to do so as soon as possible. External drives can fail as well as internal drives.
Win XP MCE 2005 suddenly is unable to "see" the contents of my music storage folder in a Maxtor external hard drive connected by USB, instead showing the folder in Win Explorer and in My Computer as being empty. Once in a while it shows the contents when I open Win Explorer, but usually not. Running checkdisk doesn't help. Thanks.