Found my Dad's old iPod 4G (clickwheel, b&w screen) at the back of a drawer, couldn't remember why he got rid of it. Charged it up, all seems to work except when you move it, you can feel the hard drive clicking and the song stops. This freezes the unit or crashes it. I'm fairly confident it's a hard drive issue - so what can I do to get it up and running again? Are they easy to take apart? I guess I can get a replacement drive (and I might as well get a battery at the same time!) on ebay, but can I upgrade it to a solid state drive? If so, is it a Compact Flash card I need? Would very much appreciate a link to a trusted site/guide on how to upgrade these old things. Can't bear to throw it away!