[Celtman]

The existence or non-existence of God is a belief, not a fact.

      Balderdash.  Facts are facts, and truth is truth, regardless of knowledge, and regardless of belief.  The Earth has always been round, even when most people believed it was flat.  God exists, even though some do not believe it.

[Modernman]

The Earth has always been round, even when most people believed it was flat. God exists, even though some do not believe it.

There is no way for humans to prove factually whether or not God exists. All we can do is speculate. So, the existence of God is a different question than whether the Earth is round. Simply stating that God exists does not prove that hypothesis.