This study enrolls patients who have a viral load of at least 200, but less than 10,000 copies/ml. The patients are randomized into 2 treatment arms. Arm A (immediate switch) patients have genotypic resistance testing at entry. Based on the resistance test results, their antiretroviral treatment regimen is modified to a switch treatment regimen. Switch treatment initiates no later than Week 4. Arm B (delayed switch) patients continue their current antiretroviral regimen and have genotypic resistance testing when their plasma HIV-1 RNA levels reach 10,000 copies/ml or greater. Based on the resistance test results, their antiretroviral treatment regimen is modified to a switch treatment regimen. Switch treatment initiates no later than 4 weeks from the date of at least 10,000 copies/ml viral load, or from the date of an absolute CD4 count reduced by 20 percent from baseline value. Patients who never meet the switch criteria remain on study.