Death is a bad state for various kinds of organized system. Broadly speaking, a thing "dies" when its homeostasis fails and it is no longer able to maintain a controlled environment within its internal structures. Most living systems are unrecoverable from this state without external aid due to extensive use of volatile memory as well as rapid irreversible degradation upon homeostatic failure; this is less true for infomorphs due to their ability to be cleanly backed up and run in emulation.
It's already far too late.