when i open my ipod classic only the apple logo and X mark was appear. this problem was started when I let it battery low. I didnt charge it about 2 weeks and then it happens.
See here: iPod Displays a Red "X" Icon
Note that if it's often a sign of a hardware issue usually with the iPod's Hard Drive. If possible, schedule an appointment at your local Apple Store/Genius Bar to have them verify that for you.
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