Hey guys. My girlfriend recently bought a new ipod Nano because her old one died. However she had to update Itunes to use it but for some reason Software update kept giving us a weird error message. I suspect a system file may have become corrupted. I suggested she let me reinstall the OS on her aluminum macbook pro but she told me her cd drive no longer works. She has AppleCare but there is a dent where she dropped and she is afraid they may not cover it. So my question is if all else fails can I buy her a cheap external drive and reinstall the OS from there or no. I googled the subject but I got mixed results.