I wonder what your motivation is to disprove the existence of God.
I look back back on human history as far as it can be traced by archeologists. The belief in a greater power, as witnessed by the preparation of the dead for a life beyond, has been around for 40 millennium. I suppose one can conclude this is a chicken or egg argument. Which came first, God or the belief in God? That question, of course, cannot be answered using scientific or mathematical analysis - at least not now.
However, one must be impressed that an abstract concept such as God has remained a part of virtually all human cultures. There have been very few cultures were God has not been recognized in some form (ie, the former Soviet Union). However, over time all people of all cultures eventually re-cultivate a faith in a higher power in some form.
You can't say that about any other abstract concepts that have remain a part of human culture for so long - except perhaps the desire to make war.
I will agree with you that for someone to hold a "true" belief in God, one must experience some form of personal revelation. Simply to hold a faith in God because a particular belief system is passed down by from family or friends cannot be as strong as someone who has had a personal experience.
Admittedly, a lot of sociological mysteries surround the practice of religion and why people react the way the do - something deserving of further study. Even so, I don't see where trying to disprove someone's belief system through logic will have any positive purpose.
