This experimental study aims to determine pre-service teachers' achievements and key factors that affect the learning process with regard to problem-based learning (PBL) and lecture-based computer course (LBCC) conditions. The research results showed that the pre-service teachers in the PBL group had significantly higher achievement scores than those in the LBCC group. Moreover, challenging, creativity, cognitive and affective attainments, and group aspects are regarded as positive learning keys in the PBL group; by contrast, in the LBCC group, the ease of learning and effective learning are found as positive learning keys, while superficial learning and adverse affective aspects are negative learning keys. Finally, these findings are discussed in terms of pre-service teachers' learning and skills and also the learning approaches used in the study.