Open the case with a screwdriver, take out the HD, and send the rest to the dump worry-free. (You should have no trouble identifying the HD if you give it a moment or two of thought.)
Also, make sure there isn't a disc in the optical drive.
Then you can take to the HD with a hammer, a giant electro-magnet, aqua regia, whatever, and sleep tight.
Edit: Outside of the HD, everything inside a computer case is dead hardware, i.e. the RAM is memoryless (because it's "volatile memory..." requires power to maintain its storage capability), and the rest is just circuitry.
Last edited by artie505; 04/19/11 08:45 PM.