AMENDED: Dropping the ddI component and open only to children with encephalopathy meaning they are losing milestones, this is equal to a P2 CDC rating . Testing the difference in intermediate vs continuous AZT. 12/1990. Original design: Children are first evaluated for randomization according to whether they have or do not have evidence of neurodevelopmental deficits at the time of the initial pretreatment evaluation. Patients are assigned to 1 of 3 groups, to receive AZT (1) by continuous infusion; (2) by oral, intermittent (every 6 hours) dosing; or (3) by oral sustained-release dosing. If the oral sustained-release formulation is not available when this study begins, it will begin with only the first 2 groups. The sustained release preparation will be evaluated as soon as it is available. Patients will be tested to measure physical or biological improvement in neurodevelopmental function.