Little is known about what treatment combinations are best for HIV infected children. This study examined the long-term effectiveness of different anti-HIV drug combinations in children and strategies for switching treatment if the first treatment does not work. The study enrolled children who had not previously taken anti-HIV medication. Participants in this study were recruited in the United States, South America and Europe. Some European children may also enroll in a substudy that will observe changes in body fat in children taking anti-HIV medications.
Inclusion Criteria: * Older than 30 days and younger than 18 years of age (may enroll up to the day before their 18th birthday) * HIV infected * Not previously on HAART or received anti-HIV drugs for less than 56 consecutive days after birth to prevent mother-to-infant HIV transmission. Participants who have previously received nevirapine for the prevention of mother-to-infant HIV transmission are not eligible for this study. * Willing to use acceptable methods of contraception Exclusion Criteria: * Grade 3 or 4 clinical or laboratory toxicity. More information on this criterion can be found in the protocol. * Active opportunistic infection or a serious bacterial infection at the time of study entry * Pancreas, nervous system, blood, liver, or kidney problems that make it impossible to take study medications * Taking any medication that cannot be combined with the study medications in first-line therapy * Received therapy for cancer * Pregnant or breastfeeding