Fosamprenavir Versus Other Protease Inhibitors

Inclusion Criteria: * Be on your first protease inhibitor (PI) containing regimen, and the regimen must consist of a PI +/- ritonavir and 2 Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (N\[t\]RTIs). * Have a plasma HIV-1 RNA level (viral load) at screening of less than 400 copies/mL, for at least 3 months prior to Screening and at Screening while on your current regimen of a PI +/- ritonavir + 2 N(t)RTIs. * Females must not be pregnant or breastfeeding or plan to become pregnant during the study. * Females of child-bearing potential must agree to use one of the approved methods of birth control. Exclusion Criteria: * Not able to follow the medication schedules and attend the study visits for the entire length of the study. * Have any other illnesses, laboratory test results, medication use, allergies, or medical conditions that would make it unsafe for the subject to participate in this study. * Currently be enrolled in any other research studies that could affect the subject''''s HIV-1 RNA levels.