[AS PER AMENDMENT 8/27/97: Patients with 2 consecutive HIV RNA measurements at least 500 copies/ml at week 16 or anytime thereafter are given the option to receive open-label treatment with IDV plus EFV plus ABC, or to seek the best available therapy outside of the study. NOTE: Patients who choose the open-label combination may take other prescribed nucleoside analogs provided outside the study.] [AS PER AMENDMENT 12/17/97: It is strongly recommended that patients who reach a confirmed endpoint and elect to receive open-label therapy consider adding additional approved (and novel, if possible) antiretroviral agents to their open-label regimen.] [AS PER AMENDMENT 1/12/98: Patients who choose the open-label combination may receive other approved antiretrovirals obtained outside the study provided the ACTG 368 team approves the combination.] [AS PER AMENDMENT 8/7/98: Subjects will take study medications for a maximum of 96 weeks, depending on their time of study enrollment.] [AS PER AMENDMENT 3/10/99: A 24-week extension, which will end July 30, 1999, has been added to the study. The extension applies to subjects currently on blinded Step 1 treatment, on open-labeled Step 2, or on study but off treatment. Subjects are to be unblinded in their study treatment and followed for the remainder of the extension. Subjects continue on their current study drug schedule. Subjects on blinded IDV plus EFV who, upon unblinding (not failure) decide to add prescription ABC to their regimen, will be considered off study treatment and will be followed for the duration of the extension; those already registered on Step 2 will continue their Step 2 therapy. Any subject who does not wish to continue on the study extension will be unblinded to their original randomized regimen. Subjects who experience virologic failure during the extension should seek best available treatment following current recommendations to use as many approved, novel antiretroviral agents as possible. The new drug regimen may incorporate any or all of the study drugs.]