The Safety and Effectiveness of Didanosine Plus Stavudine Plus Nevirapine Combined With MKC-442 in HIV-Infected Patients Who Have Not Had Success With Protease Inhibitors

Inclusion Criteria You may be eligible for this study if you: * Are at least 18 years old. * Are HIV-positive. * Have experienced treatment failure on a previous anti-HIV drug combination that contained at least one protease inhibitor. Your viral load must be between 5,000 and 50,000 copies/ml after 6 months of continuous treatment with that drug combination. * Agree to use a barrier method of birth control (such as condoms) during the study. Exclusion Criteria You will not be eligible for this study if you: * Have a history of certain serious medical conditions, including pancreatitis, neuropathy, untreated seizures, or AIDS-related cancers, except Kaposi's sarcoma (KS). * Are enrolled in another anti-HIV drug study while participating in this study. * Have ever taken NNRTIs (such as NVP or MKC-442). * Have ever taken ddI or d4T. * Have taken certain medications within 30 days prior to study entry, including medications that affect your immune system (such as corticosteroids, interleukin-2, or interferon). * Abuse alcohol or drugs. * Have received chemotherapy or radiation therapy within 30 days prior to study entry. (Local radiation therapy is allowed.) * Are allergic to any of the study drugs. * Are pregnant or breast-feeding.