To take something apart or down is to dismantle it. If you dismantle a computer to see what it looks like inside, you better know how to put it back together, or you might be looking at the inside of your room for awhile.
Dismantle is a verb used for both physical things and ideas. You can dismantle a campground by taking down the tents and breaking apart the fire logs, or you can dismantle a government by going against its leadership and bringing down its rule. Often when you dismantle something, you take away its ability to work, as with a nuclear warhead, but you can also take apart decorative or non-working things, as when you dismantle a science-fair display or a city made of blocks.