The enemy changed the Bible to make the other versions.

Yes. The King James Bible is the Bible. All other English language "versions" have changed the Word of God. How can "let's change the Word of God" ever be a good idea when the Word is God? Think of where we might be if we all had the exact same Bible and none other existed. 

So what happened? How did it happen? How did the specific term Holy Ghost refer to the Father's spirit/will get replaced by the Holy Spirit, a catchall term for the Spirit of God? What does the Bible say about this?

The love of money is the root of all evil. People (and publishers) who love money changed the Bible to sell books and cash in on religion. Changing the Word of God is, by definition, the root of evil because the Word is God.

• For the love of money is the root of all evil: which while some coveted after, they have erred from the faith, and pierced themselves through with many sorrows. 1 Timothy 6:10.

There is no excuse for anyone who never bothered to learn of Him, Jesus-the Word, on their own. 

• Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find rest unto your souls. For my yoke is easy, and my burden is light. Matthew 11:29-30.

Accordingly, many may miss their calling of God because the "version" of the Bible they follow prevents them from knowing the Holy Ghost is the means to communicate with the Father. 

• Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost. Acts 2:38.

Caution: Please do not replace Holy Ghost with Holy Spirit in your study of the New Testament. Doing so causes confusion. God is not the author of confusion.

• For God is not the author of confusion, but of peace, as in all churches of the saints. 1 Corinthians 14:33. 

Removing the Holy Ghost also gives rise to a cheap grace doctrine that avoids repentance and separates you from knowing the will of the Father personally and individually. 

• For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost. 2 Peter 1:21.

Today, we are missing the signs and wonders, diverse miracles, and gifts of the Holy Ghost because many people have no idea who or what the Holy Ghost is.

• Therefore we ought to give the more earnest heed to the things which we have heard, lest at any time we should let them slip. For if the word spoken by angels was stedfast, and every transgression and disobedience received a just recompence of reward; How shall we escape, if we neglect so great salvation; which at the first began to be spoken by the Lord, and was confirmed unto us by them that heard him; God also bearing them witness, both with signs and wonders, and with divers miracles, and gifts of the Holy Ghost, according to his own will? Hebrews 2:2-4.

The enemy knows if it can hide an understanding of the Spirit of God, then some people will never find their true calling to share the gospel and others will be lost as a result. Think of it this way: 

• But if our gospel be hid, it is hid to them that are lost: In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them. 2 Corinthians 4:3-4.

Preachers who don't use the purest Bible, the King James Bible, do not know the Spirit as well as they could. Most, however, will double down in defense of their versions that removed the Holy Ghost because of pride, having determined the gain in rectifying the error isn't worth it, or they like being the middleman. Others are paid to endorse a substandard "version" proving they can be bought.

It's worth mentioning that many of the stalwarts rejecting the notion they should return to the pure Word were taught to use a version replacing the Holy Ghost with the Holy Spirit since their seminary days. The problem is that, like all institutions of higher learning, publishers sell their textbooks to the institutions and the professors. The King James Bible is free!

Thus, if a seminary uses a version of the Bible that changes the original scriptures of the King James Bible, the error gets passed along as evil is considered good. 

Comment: Please don't be one of those preachers, teachers, etc., who face Jesus in the end knowing you didn't share the purest form of Him to feed His flock. Read John 6:47-71 knowing the Word of God is God and the "bloodline" of Jesus is the Spirit. His flesh is the shewbread (spiritual food). If the Word is our spiritual food, why don't the members of the body of Christ demand the purest food, the pure Word of the King James Bible?

Yes. Jesus said:

A certain man had two sons: And the younger of them said to his father, Father, give me the portion of goods that falleth to me. And he divided unto them his living. And not many days after the younger son gathered all together, and took his journey into a far country, and there wasted his substance with riotous living. And when he had spent all, there arose a mighty famine in that land; and he began to be in want. And he went and joined himself to a citizen of that country; and he sent him into his fields to feed swine. And he would fain have filled his belly with the husks that the swine did eat: and no man gave unto him.

And when he came to himself, he said, How many hired servants of my father's have bread enough and to spare, and I perish with hunger! I will arise and go to my father, and will say unto him, Father, I have sinned against heaven, and before thee, And am no more worthy to be called thy son: make me as one of thy hired servants. 

And he arose, and came to his father. 

But when he was yet a great way off, his father saw him, and had compassion, and ran, and fell on his neck, and kissed him. And the son said unto him, Father, I have sinned against heaven, and in thy sight, and am no more worthy to be called thy son. But the father said to his servants, Bring forth the best robe, and put it on him; and put a ring on his hand, and shoes on his feet: And bring hither the fatted calf, and kill it; and let us eat, and be merry: For this my son was dead, and is alive again; he was lost, and is found.

And they began to be merry. Now his elder son was in the field: and as he came and drew nigh to the house, he heard musick and dancing. And he called one of the servants, and asked what these things meant. And he said unto him, Thy brother is come; and thy father hath killed the fatted calf, because he hath received him safe and sound. 

And he was angry, and would not go in: therefore came his father out, and intreated him. And he answering said to his father, Lo, these many years do I serve thee, neither transgressed I at any time thy commandment: and yet thou never gavest me a kid, that I might make merry with my friends: But as soon as this thy son was come, which hath devoured thy living with harlots, thou hast killed for him the fatted calf. 

And he said unto him, Son, thou art ever with me, and all that I have is thine. It was meet that we should make merry, and be glad: for this thy brother was dead, and is alive again; and was lost, and is found.