A Randomized, Open-Label, Phase III Study of ABT-378/Ritonavir in Combination With Nevirapine and Two Nucleoside Reverse Transcriptase Inhibitors (NRTIs) vs. Investigator Selected Protease Inhibitor(s) in Combination With Nevirapine and Two NRTIs in Antiretroviral-Experienced HIV-Infected Subjects

Inclusion Criteria Patients may be eligible for this study if they: Are at least 12 years old. Are HIV-positive and have a viral load (level of HIV in the blood) of 1,000 - 100,000 copies/ml. Are currently taking an anti-HIV drug combination that includes 1 PI and 2 NRTIs, and that has not been changed in at least 12 weeks. Are naive to (have never taken) at least 1 NRTI, other than zalcitabine or abacavir. Agree to abstinence or use of an effective barrier method (e.g., condom) of birth control. Exclusion Criteria Patients will not be eligible for this study if they: Have an active illness. Have received treatment for any active opportunistic (AIDS-related) infection within 30 days of study entry. Have ever received a nonnucleoside reverse transcriptase inhibitor (NNRTI). Have received investigational (not yet approved by the FDA) drugs within 30 days of study entry. Have received treatment with a PI other than their current PI. Are receiving chemotherapy for cancer. Are pregnant or breast-feeding.