iPod keeps running into errors when syncing

I recently bought a classic from a friend (don't know if it's older classic or new-wave one) and whenever I connect it to my computer a message pops up saying there's an error with my device. When I try to sync, it loads anywhere from a couple to a couple hundred songs, then stops, often converting the music just put on into the "other" category rather than recognizing it as music. I've restored it countless times, tried using a different computer (that is also on a different operating system), checked for iTunes and iPod updates alike, enabled and disable disk use, and nothing seems to be helping. Is this iPod just toast, or is anyone else experiencing this?