This leading no where, not that is was supposed to. That's why I seldom wish to get into discussions on religion - it never ends. We will never know. One can accept, or reject it. I can live with the thought that I will not know everything in my life.
But since it is really quiet at work (hope it won't be like that the rest of the year), I can answer this one - where did God come from? God came from our thoughts. It is a creation of our minds. We need this created God to fill the voids left by unexplained mysteries (or uncertainties). We (us, humans) needed something superior to the forces of nature, some being that at will could calm great storms, tame the weather, and so, if we are good and obedient, he (she?) will be appeased and reward us with fair weather, successful crops, plentiful harvests. Even help us eliminate our enemies (Jews found that god!). It's been millennia since we thought of this god, and we still haven't found him. Some of us have speculated that God is within us, we need not look at the stars and out too look for him, we just have to close our eyes, keep quiet, and search ourselves, and find peace within us. There, we will find God.
Cheers!