The national average Microsoft Office Specialist (MOS) Excel certification exam pass rate on the first try is relatively low. The problem addressed in this study was the effectiveness of asynchronous instruction with adult learners using computer-based instruction (CBI) programs and if these interactions affect the successful completion of the Microsoft Office Specialist (MOS) Excel certification exam. The purpose of this qualitative phenomenological study was to gain a better understanding of the lived experiences of adult learners' asynchronous interactions using computer-based instruction (CBI) programs and if these interactions affected the successful completion of the Microsoft Office Specialist (MOS) Excel certification exam. The theoretical framework that guided this study was Knowles's theory of andragogy. Andragogy is the study of adult learning. In this qualitative phenomenological research study, 10 adult learners who used a CBI program to prepare for the MOS Excel certification exam participated in an in-depth interview process. From the findings of this qualitative phenomenological study, it was revealed that adult learners enjoyed interacting with CBI programs and felt these programs contributed to the successful completion of the MOS Excel certification exam. Three major implications were found during this study: (a) adult learners enjoy asynchronous CBI programs that are self-directed and put the learner in charge; (b) adult learners interacted positively with CBI programs that include interactive media; (c) adult learners felt that the learning material of asynchronous CBI programs needed to focus on relevant goals and learner outcomes. Recommendations for future research should explore the lived experiences of adult learners who did not use a CBI to prepare for the MOS Excel certification exam. The second recommendation is to conduct a qualitative exploratory case study to provide an in-depth understanding of the experiences of the phenomenon and possibly collect new perspectives from adult learners. The third recommendation is to embark on a quantitative ex post facto study to discover if there is a correlation between the amount and length of time spent interacting with CBI programs and the successful completion of the MOS Excel certification exam. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]