If you believe the Bible to be the inspired word of God given to man for guidance and direction then you have to ask yourself why He would allow it to become corrupted. Doesn’t He have the power to prevent something like that?
Second, most of what you read about the Bible’s authenticity is written by people who are trying to convince you that it’s unreliable. The fact that they have a PhD in Theology makes no difference. Many theologians don’t believe that the Bible’s really the Word of God, because many seminaries teach them that. But the fact remains that it’s the most thoroughly validated book in history.
According to Christian Apologetics and Research Ministries (www.carm.org), New Testament documents are better preserved and more numerous than those of any other ancient writings. There are 5,686 Greek manuscripts in existence today for the New Testament, thousands more than for any other ancient text. Because the copies are so numerous, they can be cross checked for accuracy. This process has determined that the internal consistency of New Testament documents is about 99.5% textually pure. In addition there are over 19,000 copies in the Syriac, Latin, Coptic, and Aramaic languages. The total supporting New Testament manuscript base is over 24,000 manuscripts.
Do you realize the magnitude of the conspiracy that would have to have existed over the centuries in order to pass off an adulterated work as pure? Many of these manuscripts pre-date the Catholic Church by several centuries. People who promote this kind of nonsense are only able to do so because of our lack of knowledge about the Bible’s origins and our lack of faith in God’s word.
Third, you’re concerned about the claims of non-believers whose only source is a TV “documentary” that you’ve never seen and whose authors you know nothing about.
But really, it all boils down to this. If you believe the Bible and it turns out to be wrong, you can always tell God that you took Him at His word. And if there is no God, you won’t be any worse off for knowing that. You’ll only be as dead as when you found out. But those who don’t believe the Bible and find out too late that there is a God, will have to admit that they refused to take His word for things and will suffer an eternity that’s disagreeable beyond imagining. In short believers have nothing to lose by believing and may gain incredible blessings, and unbelievers have nothing to gain by not believing and may suffer incredible punishment. Who are the winners and who are the losers?