When you got saved you received a new spirit. That spirit is perfect and wants to please God. However your mind is not new, you have the same mind you had when you were a sinner. And so God says your mind has to be transformed by reading the Word of God. Satan knows that your mind is still the same so he try's to attack your mind. The battle ground here on earth is for the control of your mind. The only weapon satan has is to attack you thru your thoughts. He tries to discourage you by telling you about all of your failures, sins, wrong choices and bad relationships you have had. He wants to take control of you by controlling your mind. He has no power so he uses deception and lies to try to deceive you.
Evil spirits still exist but they have no weapons. Jesus defeated them at the cross. All they can do is attack your mind and try to get you to do things that are against God's will. They can not live inside of you because God lives inside of you and won't allow it. They are powerless to harm you in any way. Put on full armor of God Pray a hedge of protection around you and your family Bind all evil sprits out of your life and your families life. What you bind on earth God will bind in heaven,
chosenbygod, I am praying for you