The objectives of this study are to explore the metabolic toxicities associated with lopinavir/ritonavir (LPV/r) plus saquinavir mesylate (INV) versus LPV/r plus Combivir in antiretroviral naïve subjects and to assess the overall safety, tolerability and efficacy of LPV/r plus INV versus LPV/r plus Combivir in antiretroviral naïve subjects and to assess the pharmacokinetics of 400 mg INV taken twice a day (BID), 600 mg INV BID and 800 mg INV BID in combination with 400 mg lopinavir/100 mg ritonavir plus 150 mg lamivudine/300 mg zidovudine BID.