Patients take open-label Combivir plus abacavir plus efavirenz for 48 weeks. [AS PER AMENDMENT 4/20/00: Patients taking Combivir plus abacavir at Week 24 receive the triple-nucleoside-combination tablet (TCT) (abacavir/lamivudine/zidovudine) beginning at Week 24 and continuing through Week 48, in combination with efavirenz (or nevirapine if the patient has made a protocol-allowed substitution). Patients not taking Combivir and abacavir at Week 24 will continue in the study on the substituted protocol-allowed drug regimen, provided their plasma HIV RNA is below 400 copies/ml at 24 weeks.] Following enrollment on Study Day 1, on-study evaluations (virologic and safety) are performed at Weeks 2, 4, 8, 12, 16, and then every 8 weeks through Week 48 (end of study). CD4 evaluations are performed at baseline and at Weeks 4, 8, and then every 8 weeks through Week 48. Immune reconstitution testing is performed at baseline and at Weeks 12, 24, and 48. Patients complete the PMAQ7 version 1.1 medication adherence questionnaire at Weeks 2, 8, 12, 24, and 48 (or at their last study visit). All patients are requested to return for a post-study follow-up evaluation 2 to 4 weeks after the last on-study visit. Patients must have a plasma HIV RNA less than 400 copies/ml at Week 24 in order to continue in the study.