NOTE: During the single dose portion of this study, patients may be untreated or may continue treatment with their current nucleoside antiretroviral therapy. During multiple dose administration of Viracept, antiretroviral therapy will be intensified by either adding or modifying therapy. Antiretroviral therapies will be limited to those currently licensed including zidovudine, lamivudine, stavudine, didanosine or zalcitabine.