In order to determine the ability of a drug regimen to decrease viral load after drug treatment has failed, it is best to test a variety different of drug "cocktails" (drug regimens). The drug cocktails in this study include 2 new nucleoside reverse transcriptase inhibitors (NRTIs), efavirenz (an NNRTI, non-nucleoside reverse transcriptase inhibitor), and either 1 or 2 protease inhibitors. It is important to include multiple drugs from different groups in a drug cocktail since combinations containing fewer drugs are likely to fail.