There weren't any screws in my Classic except a few small ones holding various internals together. A Precision screwdriver set from Wal-mart works for those. The case is actually held together with clips under the fascia. Here's the How-to that I used to disassemble mine Ipod Classic Disassembly
. There is nothing user serviceable really in there though. The hard drives are custom 1" units and the cost of a new drive is almost the 2/3 of the cost of a new iPod. Other parts are similar stories, they can be found but are hard to find and more expensive then just replacing the iPod.