Bascially your assumption is that something that looks and works like an Intel CPU carry out an operation, that can be called a computation, everything else is not.
But sorry this is not the only method to "compute". You are limiting the definition of computiation and try too hard to justify all false assumption that you have been made.
My assumption is that something like a Turing machine, or like a reduction in Lambda calculus, or like a demonstration with the basic laws of predicate logic (all known equivalent models of computation) is a computer.
