The purpose of this study is to determine whether HIV-1—infected patients, who are virologically suppressed on a regimen of 2 nucleoside reverse transcriptase inhibitors plus any third agent but are experiencing safety and/or tolerability issues, will maintain virologic suppression after switching to a regimen of heat-stable ritonavir boosted atazanavir, 300/100 mg, once daily plus raltegravir, 400 mg, twice daily.