The S10 does not have a user removable back. If you absolutely must get in to it, be aware you will almost certainly cause damage to the unit.
You'll need a heat gun, prying tool, spudger, as well as a suction cup to make things easier. Heat the outside edge of the back along the bottom, and slowly separate the backing from the chassis. Be aware the glue used on the back is extremely strong, and may require excessive heat. Repeat all the way around the back until it can be removed.
