Patients are randomized to one of two study arms. Patients in Arm 1 receive SQV-SGC plus two [AS PER AMENDMENT 11/24/99: one or two] NRTIs of choice. Patients in Arm 2 receive SQV-SGC plus NFV plus one or two NRTIs of choice. All participants are evaluated by physical examinations and laboratory tests during the study and are followed for incidence of death, cancer, or fetal abnormality. NRTIs are not provided as part of this study. [AS PER AMENDMENT 11/24/99: This study is closed to accrual. All subjects on follow-up (Cohort 1) are given the option of either discontinuing participation in ACTG 397 or participating in the next phase of the study (version 2.0). Those electing to continue participation constitute Cohort 1A. The adjusted Arm 1 regimen consists of SQV-SGC plus ritonavir plus one or two NRTIs. Ritonavir is not provided as part of this study. The Arm 2 regimen study drugs have not changed but the maximum allowable dose of SQV-SGC has increased from 1,200 mg twice-daily to 1,600 mg twice-daily. Participants continue to be followed with physical examinations and laboratory evaluations that include an intensive pharmacokinetics study on Day 14 of the new regimen.]