When someone preaches against sin and how it brings God's judgment, what is the implication? Is it "Stop sinning or else!" or is it "You have no hope in yourself!"? To the one who doesn't hear, if either one of these messages hits home, it's the former - and that person will try and earn his way to heaven. But to the one who hears, the former sinks in and that person turns to Christ. But do they do so because they choose to? No. It's because the Holy Spirit was working in them as you quote in those verses. They aren't forced, but just as the sleepwalker who awakes to find himself stepping over a cliff, the sinner doesn't need to be convinced of his situation - he can't save himself. All that is the work of God. He wakens the sinner and shows him his situation and then saves them as they call out to Him. For if they TRULY see and hear, they will know beyond a shadow of a doubt that they can do nothing of themselves and only He can save them. But even that is a work of His Spirit.
EDIT : In summary, the opening of the eyes and ears reveals the truth and there is no need to convince that person (who has been so enlightened) to believe. All this is of God.