itunes stops responding when adding music

I have an iPod classic (I think 5th gen) it had worked great for a long time and then a few weeks ago it just froze. After it froze I forced restarted it and all my music was gone. Now I am trying to add all my music and everytime to go to do it (whether on mac or pc) a few files will load and then itunes will freeze and stop responding. I am running itunes 10.6.1 on my pc and 11 on my mac and I have restored the ipod a couple times but it doesn't seem to make a difference. I would love any advice or help because this is extremely frustrating. Thanks