A study comparing Indinavir plus Ritonavir plus 2 NRTIs vs. Nelfinavir 1250 plus two nucleoside reverse transcriptase inhibitors (NRTIs) in the treatment of HIV positive patients who have not responded to or are intolerant to a non-nucleoside reverse transcriptase inhibitor (NNRTI) containing treatment.

Inclusion Criteria:

• At least 18 years of age
• HIV positive
• No active heart disease

Exclusion Criteria:

• Pregnant or breast feeding
• Unwilling to use birth control or abstinence to prevent pregnancy
• Received an investigational drug or vaccine within the past 30 days or is planning to receive other investigational study drug/vaccine or interferon while in the study
• Plan to receive NNRTIs while in the study
• Received therapy which lowers body's ability to fight infection within the past 30 days or while in the study
• Alcohol or substance abuse
• Hepatitis