Patients are randomized in a 2:1 scheme to 1 of 2 treatment groups. Group 1 receives GW433908 plus abacavir (ABC) plus lamivudine (3TC); Group 2 receives nelfinavir (NFV) plus ABC plus 3TC. Patients undergo safety and efficacy assessments at the Screening Visit, Day 1 (Entry), and Weeks 1, 2, 4, 8, 12, 16, 20, 24, and every 8 weeks thereafter. A follow-up visit is performed 4 weeks after the permanent discontinuation of study drug. Detailed assessments for the development of lipodystrophy/fat redistribution occur at Day 1, Week 24, Week 48, and every 16 weeks thereafter. Patients have examinations and laboratory tests performed at visits.