3rd gen ipod touch will not sync having done so on coutless occassions and now it just does 1 phase of sync

I have a 3rd gen 8gb ipod touch when I try to sync it it goes through phase one of the sync and then says sync complete, changing nothing on the ipod

if I reset my Ipod and it wipes everything off and then it still wont sync I will have a worthlerss ipod no tune or apps on it