I can't sync my music anymore to my Insignia NS-SV anymore?

[Patrick3]

All of a sudden, I cannot sync music(MP3/WMA files) to it anymore (I use WMP). When I click to sync it, it goes up to "100%" completed, but just freezes my mp3, and won't actually show the "sync completed". So then I decided to just drag and drop to my "music" folder, but it shows a message saying my mp3 is disconnected or something of that sort. The player is connected properly and everything, and I have the latest firmware installed. Also, syncing other things such as photo and video still works perfect. It's just that for no apparent reason, I can't sync my music anymore: any ideas what's up? I've been syncing my music for the past three years, and have experienced no problems.
Thanks.