iPod Classic won't sync and crashes iTunes. Suggestions?

Hi, hopefully someone can help me!

I have a 80GB iPod classic for 3/4 years, never had any syncing issues until now that weren't fixable by a reset.

However a few days ago I was at my parents' house and charged my iPod using their computer. The first time there was the standard message "This iPod is synced with another library" etc etc but subsequently it crashed iTunes. It was recognised by the computer as a portable media device, all the normal folders were there etc.

Now that I'm with my regular laptop, I'm having the same issues but have realised that the iPod won't sync. It crashes iTunes when it's connected and when I disconnect the iPod, should iTunes works but it displays the message: "The iPod cannot be synced. The required folder could not be found"

Any suggestions on how to fix this? I've tried updated my iTunes software and resetting the iPod (pushing menu and centre), but neither has had an effect.

Edit: I should add that since charging the iPod on the other computer, I have also had issues with the click wheel, sometimes it works, sometimes it doesn't.