Patients ages 18 or older with HIV infection, who are not pregnant or breastfeeding, who do not have a known allergy to atorvastatin use, and who have not had a serious illness or infection that required hospitalization within the 30 days before entering the study may be eligible for this study. They will be assigned to random groups: one that to receive atorvastatin and the other to receive a placebo, which has no effect on cholesterol or ability of the HIV infection to multiply. Patients will remain in their groups and treatments for 8 weeks. At the completion of 8 weeks, no matter the study group, all patients will be required to discontinue all study-related medications for 4 weeks. After that period, the study assignments will be switched, so that those previously taking the placebo will take atorvastatin, and vice versa. The study will proceed for another 8 weeks, followed by a period of stopping study-related medications and patients being observed for 4 weeks. Throughout the study, patients will have regularly scheduled visits at the clinic. At those visits there will be collection of blood samples, assessments of symptoms, physical examinations, and questionnaires to complete. Blood tests may require fasting beforehand, and blood samples will be used in standard tests, including those regarding the liver, kidneys, muscles, blood cells, and pregnancy status. Specialized blood tests will determine viral load, effects of the drug on the immune cells, and genetic influence on the drug's effectiveness. The time spent for procedures during clinic visits...