I have a 80gb iPod 5g that I wasn't using and decided to let a friend of mine borrow and use it for a couple of weeks while he was going out of town. I told him that he could format it and put whatever he wanted on it because I had all my music backed up and wasn't worried about it. When I said "format" what I really mean't was he could hook it up to iTunes and use the restore option thus clearing anything on it. Unbeknownst to me he was using the Linux operating system and since I said "format" he actually formatted the iPod to FAT and ever since he did that the iPod just makes a loud clicking noise until the battery dies and neither Linux, Windows, or OSX will notice it. It just says "please wait. low battery" then gives a sad ipod icon. Then repeats.