The purpose of this study is to compare the anti-HIV efficacy, safety and effect of serum lipids of two boosted protease inhibitor-based HAART regimens (ARV/RTV v. LPV/RTV) in HIV-1 infected subjects who have experienced their first virologic failure while receiving a NNRTI-containing HAART regimen.

Inclusion Criteria:

• Patients ≥ 18 years of age infected with HIV
• Plasma HIV RNA ≥ 1000 copies/mL and CD4 cell count ≥ 50 cells/mm3
• Currently receiving a NNRTI-containing HAART regimen or not currently receiving a NNRTI-containing HAART regimen and have not been treated with an alternative regimen since the documented virologic failure (with genotype performed within 2 weeks of the discontinuation of the failing regimen and the genotype report is available)
• The failing NNRTI-containing regimen must be the patient's first virologic failure on treatment and contain a NNRTI and at least 2 NRTIs. The regimen must have been administered for at least 24 weeks and the patient must have documented virologic response to the regimen (HIV RNA < 400 c/mL)

Exclusion Criteria:

• Pregnancy or breastfeeding
• Reported virologic failure to two or more antiretroviral regimens
• Active AIDS-defined opportunistic infection or disease
• Proven or suspected acute hepatitis within 30 days prior to study entry