I POD CLASSIC 60GB

after many months without sync ( this ipod was at the office ) and connected the ipd to my mac at home . the system requested to restore the ipd, that know lost all the music. my muci library is ok but it does't sink anymore ( i am unable to move my library into the ipod ) my mac book pro is updated with the lastest mac software and i am not able to upload music in this ipod classic . any help ?