AMENDED: Patients are randomly assigned to one of two treatment regimens. They receive AZT (or other antiretroviral agent) with or without ACV. Treatment Plan 1: AZT along with placebo at the same time. Treatment Plan 2: AZT and ACV. Therapy is for 104 weeks with an optional extension of 24 weeks or until the end of the study whichever comes first. The maximum duration of therapy for any patient will be 128 weeks. Medication is dispensed on a biweekly basis for the first 4 weeks, then every other month for the remainder of the study. Original design: Patients are randomly assigned to one of four treatment plans to receive AZT alone or AZT and ACV. Medications are given every 4 hours (q4h) orally (PO) while awake (WA). A total of 5 doses/day are given. The per dose schedule for the four plans are: Treatment plan 1: AZT plus placebo (an inactive medication) substituting for ACV. Treatment plan 2: AZT and AZT placebo along with an ACV placebo. Treatment plan 3: AZT and ACV. Treatment plan 4: AZT and AZT placebo and ACV.