Ipod has apple icon, then red X, nothing else.

As it's booting w/ the apple logo, listen to the iPod, if you hear nothing at spinning inside, you most likely have a broken logic board. If you hear spinning but also repetive clicking, you have a broken hard drive.. You can try to replace the part yourself, it is available on any auction website. There are iPod classic Repair services that can fix it for you, but if you're a little tech savy you should use an iPod repair guide that teaches you how to do the repair yourself.