Arm 1: 3TC plus ZDV plus IDV. Arm 2: 3TC plus ZDV plus IDV plus EFV. Arm 3: 3TC plus ZDV plus IDV plus NFV. Patients are followed for at least 72 weeks [AS PER AMENDMENT 2/16/99: 96 weeks] beyond the enrollment of the last patient. Patients who experience virologic relapse will have the option of continuing randomized study medications, switching to Step 2 treatment, switching to another ACTG study, or seeking best available therapy for the remaining weeks of the study. Step 2 treatment consists of abacavir or 2 NNRTIs plus efavirenz plus amprenavir or another protease inhibitor. [AS PER AMENDMENT 4/3/00: Optimally, Step 2 treatment regimens should contain 3 or 4 drugs to which the virus is susceptible. If this is not possible, a drug to which the virus is partially susceptible is acceptable, but a drug to which the virus is resistant should not be included.]