The purpose of this study is to see how effective and safe it is to give 1 of the 3 following treatments to patients who may not have received anti-HIV treatment: 1) lamivudine (3TC)/abacavir (ABC)/stavudine (d4T); 2) 3TC/ABC/efavirenz (EFV); or 3) 3TC/ABC/amprenavir (APV)/ritonavir (RTV).