When you take the system drive and put it in a new box, do you rename it or do you keep the name? And when you put a fresh drive in the old box, do you give it a new name? What is with upgrading? How many of the components do you have to change until a computer loses its identity?

So a CPU is often described as the heart or the brain of a computer but where lies its soul? What determines its identity? The data on the system drive? The majority of its components?

This might sound like a not-so-serious question and it probably is but whom of you didn't already face this problem?