This study showed that predicting student errors by even the most experienced of instructors is insufficient in developing a database for anticipated errors. Instructors predicted only 39 to 54% of the wrong answers for common general chemistry problems. The same questions used by instructors were included on exams given to groups of 300 to 350 general chemistry students. All incorrect answers were closely examined to see if they could have arisen from some recognizable line of thinking. Numerical answers for similar questions were calculated by using a spreadsheet that generated all answers corresponding to errors previously identified. These answers were used to develop lesson scripts. Lesson scripts described here can be used to create material that will produce a specific reply to match anticipated inputs to a given question or problem. More than a third of the students who had difficulties with problem solving in this study were guided toward the right answer and consequently assisted in their instruction by addressing their inputs with specific responses. Lesson scripts have the power to be used effectively as a teaching aid in a variety of ways including developing better multiple choice questions, improving classroom instruction by paying attention to common errors, and creating highly interactive electronic study guides. This ultimately could raise the level of interactivity and make computers a better teaching tool.