Mav:

To me dismantle has the connotation of taking something apart permanently. At the end of WW II the United States dismantled the largest army it had ever fielded.

Disassemble to me carries the connotation that the new state of the object is temporary: I disassembled the computer desk because it wouldn't fit into the trunk (or boot for many of you).

Also, when I disassemble something, there's an implication that I am following instructions in reverse order. And, after all, one does not mantle a piece of furniture, one assembles it :)




TEd