First we have to ask what makes a person a person. It's obviously their individuality. If you grew a human in a lab with no brain therefore unable to have a personality or an ego or anything, and set it on fire or killed it in any way, it'd be unreasonable to have remorse since it's not a person. It was simply an empty husk of human tissue.

So if we agree that what makes us "us" is within our brain -- our ability to store memories and form personalities that allow us to interact with other people and things -- then we have to agree that once we die and the brain dies and rots away, all of those memories and areas within the brain making us who we are as a person are all gone as well, and therefore we are then gone.

Yes the energy that powered us is all around us. The body runs on electricity. However to say that because this electricity, this energy, is still there around us therefore we are still in existence because of that after we're dead is like saying that a Pepsi bottle I once drank soda from still exists even after it's been recycled and used to make a window.

Once your brain is gone, YOU are gone. If you want to have faith and think that you still live after death by going to heaven or you're sitting in a limbo waiting to be put into another newborn's body where you will in essence be born again, then go for it, but that is as of today science fiction.