Original design: The study's purpose is to compare the effects of zidovudine (AZT) alone to the combination of AZT and acyclovir (ACV) to determine if AZT/ACV is associated with a lower death rate and fewer AIDS related opportunistic infections compared to AZT alone, and to investigate the effect of these treatment plans on cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections. The study evaluates two doses of AZT used alone versus two doses of AZT combined with ACV. Per 12/11/92 amendment: Another antiretroviral agent may be substituted for AZT.