Sure you've looked at this then, but either Chesterton or Lewis would say the answer is the fact that the questions are built in to your being. If you have a God shaped hole there must be a God. I think the analogy was if you can experience thirst or hunger, there must be something out there to satisfy that built in need or desire, i.e., water/food. The fact that mankind has searched for an answer or a reason for his creation means there is in fact a reason and and answer. In my quest that was probably one of the more convincing.

I'm not one to try to convince anyone, honestly, just love a good back and forth about interesting subjects. Thanks and have a good day!