I guess it depends how you define dead.
By some definitions we can, but only for limited periods.
The colder it is, the longer we have to resuscitate people.
That is what AEDs do for someone who has had a serious heart attack of certain types, if applied in time they will restart someone’s heart and bring them back to life. Without such devices they are dead.
I had a friend who had a serious car accident, broke most of the bones in his body, and ended up face down in seawater in the middle of winter. He was like that for about an hour. A thing called “the mammalian dive reflex” cut in, and several teams of expert surgeons spent a couple of days working on his body kept on ice, and eventually restarted it. He did come back from the dead, but not without serious changes in his personality and memory – a lot of function had been disrupted.
Once the cells of the brain die in number, that is it for us. Our experience of being does in fact seem to be the operation of a software system running on the very complex and squishy hardware that is the human body. All of our memories and tendencies to thoughts or feelings do actually seem to be encoded in those exceptionally complex systems. And the computational complexity of those systems is vast. And there are many subsystems that are sources of randomness and novelty that ensure we all do new and unusual things from time to time (more frequently in some contexts than others).