thats the point - there are spare parts - and in fact the computer was clearly made from them (so it undoubtedly is a result of complexity)A dead person is broken. Something has to be broken for the person to die.
Your definition was:
When broken, it can not easily be reconstructed by humans.
Try the computer analogy again, and keep in mind that there are NO spare parts.
you can indicate death in an organism by various factors (lack of bioelectricity in the cells, plasma deficiency, dysfunctional organ etc) but life cannot be restored or constructed from these things.