Doctors generally treat patients in the early stages of HIV infection with the same anti-HIV drugs taken by patients who have had HIV for a long time. These drugs lower the level of HIV in the blood. However, doctors do not know whether patients who take anti-HIV drugs in the early stages of HIV infection actually live longer or have fewer AIDS-related diseases. This study will help doctors answer these questions. In the main study, doctors will look at how 2 different anti-HIV drug combinations affect the immune system. In the 2 substudies, doctors will look at how the body reacts to the hepatitis B vaccine and the tetanus vaccine. These substudies may help doctors learn how HIV-infected patients respond to new infections.