Step II will only be open to South African subjects who are virologically responding to treatment when the last enrollee into either part of Step I (Part A or Part B) has completed 96 weeks of treatment (end of Step I) . All such participants will be given ATV in capsule form at the same dose they received at the end of Step I, as well as the other antiretrovirals they were receiving during Step I. Step II will continue until ATV is approved in South Africa and readily available by individual prescription, and participants will have a study visit every 12 weeks.