How to Reseat the hard drive in an iPod classic
First, get out a Swiss Army Knife and clean your hands. Then, take out the main blade. Next, on the right hand side of the IPod, stick the blade through between the gap to open the casing of the IPod. Then, turn the ipod upside down, so that the display side is facing the ground. Cautiously open the case, being careful not to damage the attachment in the top corner. Once the case is open, carefully detach the the hard drive from the bar "thing" connected to the top of the hard drive. Next, take the hard drive out of the case and wait (you can clean with a Q-tip and rubbing alcohol if it is dirty. Then, re-insert the hard drive and reconnect it, and put the IPod back together. It should be working correctly now.