The Holy Spirit, God Almighty, will not dwell in you with some punk demon! No, that just won't happen. Sorry Ralph, you need to go back to your small mansion on the hill and making lots of money by putting fear into folks that don't know any better.
Now this is a prime example of what demons might do when it is NOT to their advantage to play along with "The Exorcist". The book of Acts, Chapter 19, records the attempt of the seven sons of Sceva, (who were "vagabond Jews, exorcists"), to exercise spiritual authority over Satan and evil spirits. When their own attempts at exorcism failed, they then tried to use authority they did not possess.
"We adjure you by Jesus whom Paul preacheth."
But the evil spirit "not moved" by all of this replied;"Jesus I know, and Paul I know; but who are ye?
And the man in whom the evil spirit was leaped on them, and overcame them, and prevailed against them, so that they fled out of that house naked and wounded."
The term "exorcist" is not of God. It was a term used by certain Jews who were involved in the occult -- the Kabbalah. If you feel that there are "spiritual problems" in your life, ANY TRUE child of God can command them to leave in Jesus' name and they will have no choice but to comply with that command. If you feel that you are being bothered by demons after you have given your heart to the Lord, YOU can command them to depart from your presence as at that point they have no right to be in you but they can still try to make you "think" (external influence) that you are still under their domination. Stay in the word of God. Read the Bible daily, even if it's no more than a chapter each evening before you go to bed.
There have been many cases of "self-deliverance" by simply confessing all your known sins to God, "binding" all unclean spirits, and then commanding them to leave in Jesus' name, and then finally; praying for salvation and meaning it with all your heart! (See "The Only Doorway" page.)
Is that all there is to it? Yes. Jesus said that He came to set the captives free... and that's all there is to it!