1. Reset or restore your iPod for a try, this can fix many general iPod problems.
2. You may try this iTunes alternative, I always use it to upload music and video to my iPod once my iTunes can't recognize my iPod, my friends recommend it to me, it's safe and works pretty well, you can also use it to copy music and video from ipod to computer for backup, it's useful when you lost your iTunes library.
http://www.ipod-trans...sfer-mediawidget.html
3. Update your iTunes to the latest version. Plug in your iPod. If iTunes can't recognize it, then in iTunes in the top left corner click help> run diagnostics. On the box that comes up, check the last two things. Click next and it should identify your iPod. I got this method from Apple technical support. Hope it helps. Contact me if you have any other question.