I appreciate your honesty about your past -- and I hope your experience will be a warning to someone who may be tempted to go down the same road you did. As you've discovered, we only cheat ourselves when we do something like this; eventually it catches up with us.
Why is it wrong to cheat, whether it's on a test or in a business deal? The main reason is because cheating is actually a form of stealing. When you cheat on a test, you're stealing from someone who worked to learn the material; when you cheat someone in business, you're robbing them of something that is rightfully theirs. The Bible says, "Do not steal. Do not lie. Do not deceive one another" (Leviticus 19:11).
My prayer is that you will turn to Jesus Christ, and by a simple prayer of faith confess your sins to Him. Then ask Him to come into your heart and take control of your life. He alone can take away your guilt, and He alone can help you build your life on a solid moral and spiritual foundation. God's promise is for you: "I will forgive their wickedness and will remember their sins no more" (Jeremiah 31:34).
Then ask God to help you overcome your deficiencies. For example, He may open the way for you to take courses to help you sharpen your skills (perhaps at night or over the Internet).