Forest Grove High School (FGHS) is a suburban school in Oregon that implemented an extensive remediation program to increase the mathematics scores of its learners taking the state-mandated competency examination, the Oregon Statewide Assessment Test (OSAT). Learners who failed at least two of the mathematics sections of the 1998 OSAT, taken when they were in the eighth grade, were enrolled in a High Intensity Learning Lab (HILL) for remediation that included the use of the PLATO computer learning system. The 2000 OSAT mathematics score for sophomores assigned to the HILL increased from 228 to 232.1. This gain was more than two times larger than that of the general learner population who did not use PLATO. In the general learner population, among those not using PLATO, percentile ranking declined from 54% to 45%, but PLATO users' percentile rank remained at 41%. However, due to a change in the cutoff scores for the OSAT, a higher pass rate did not result. Only 37% of the 10th graders in Oregon had a passing 2000 OSAT mathematics score. A significant positive relationship was identified between PLATO module mastery and the 2000 OSAT test. Learners (n=38) and teachers generally liked the PLATO system, and the FGHS principal and PLATO instructor believed that PLATO contributed to learner improvement on the OSAT. Appendixes contain the instructor survey results, graphs of OSAT achievement data, and the learner survey results. (Contains 6 tables and 33 figures.) (Author/SLD)