Can't see mp3 files in Windows 7!

Thank you for your response! I did as you suggested, but I still cannot see any of the mp3s on the device. The problem is not assignment of a drive letter, etc. The drive is clearly listed in Explorer, and I can see all of the folders on the device. The problem is that the folders all appear to be empty–I cannot see any of the mp3s event hough the drive is loaded to near capacity.

Any other suggestions would be appreciatged!