See, this is where the problem is. There is no point in moving past the part highlighted in red above if this has not yet happened. Man cannot have a true faith in god without spiritual understanding. And who is responsible for granting this understanding? God....via the holy spirit. Those who are dead in sin are not able to understand as they are "spiritually discerned." I can't "choose" to have faith, until the Holy Spirit convicts (convinces) me. It is a gift of god and not of our doing.
Dead in sin isn't exactly what you seem to be implying. Man sees God through the things around him. The things of God are written in our conscience, and we feel guilty when we do something wrong. Jesus is knocking on the door. When you finally get up and open the door, you'll have understanding because you'll be confronted with your Saviour.