One cannot "prove" something doesn't exist. Nor do all religions believe in the same type of God. For most of humanity's existence, it was reasonable to believe that the earth was stationary and the stars moved. You could see the proof of that every night.

For most of humanity's existence, gods and demons were invented to explain what seemed unexplainable. People anthropomorphised nature. The Jewish god of three thousand years ago is not the same entity they worship today. He no longer smites down his enemies or demands animal sacrifices. However, he does now promise an afterlife.

What is a reasonable person to make of the changing nature of God? Did we get it wrong for most of the hundreds of thousands of years
anatomically modern humans have been around? Are we only recently beginning to see the true God? Did homo habilis worship a God millions of years ago? What about the Australopitheci? Do gorillas worship a God?

How could the old Jewish God turn Lot's wife into a pillar of salt if he couldn't enter the universe without destroying it? And what of his
angels? They seem able to work in this world yet we don't see them anymore. Couldn't a host of Angels take command of the airwaves and proclaim the existence of God while he performed miracles on global TV in front of the world's foremost scientists (spirited from their homes and workplaces and miraculously appearing where the miracle is being performed)?

At the least such a demonstration would prove that there is an intelligent power much greater than man.

The simple fact is that God leaves no fingerprints. We know something happened but not who or what did it. The believer's quest for a proof is a reflection of their own insecurity in their belief.