You guys really don't know much about this at all.
Try reading Thomas Aquinas' 5 proofs of the existence of God, The Consolation of Philosophy of Boethius, and DesCartes' Meditations on First Philosophy if you want solid answers to all your questions. Otherwise you have no place in saying whether or not you believe in God. If you don't understand the fundamentals, you probably won't know how to properly put advanced arguments in their proper place.
I disagree. Just because I don't believe in God, and same goes for many others, doesn't mean that I deny his existence, or have to make a super advanced point as to why I don't. Just like no one should have to explain why they're religious. While many people do deny his existence, that's okay. If they don't believe in him, there's no point making them read something they don't really care for just to make advanced arguments.