Participants will be enrolled in this study for 6 weeks and will be assigned to one of two study arms, depending on their HAART regimen at study entry. Participants in both arms will also be stratified by age. Arm A participants will receive 400 mg/100 mg LPV/r twice daily along with two or more nucleoside reverse transcriptase inhibitors (NRTIs). Arm B participants will receive a regimen containing only NRTIs or no HAART. HAART will not be provided by this study. All patients will receive a single dose of ON 1/35 on Day 1 and will start the Ortho Evra contraceptive patch on Day 3. A physical exam, pap smear, pregnancy test, viral load test, CD4 and CD8 counts, and blood collection will occur at or before study entry and on Day 24. Pharmacokinetic analyses will occur on Days 1 through 3, 17 through 19, and 24.