A Randomised Trial to Evaluate the Antiviral Efficacy and Safety of Treatment With 500 mg Tipranavir (TPV) Plus 100 mg or 200 mg Ritonavir (RTV) p.o. BID in Comparison to 400 mg Lopinavir (LPV) Plus 100 mg RTV p.o. BID in Combination With Standard Background Regimen in ARV Therapy naïve Patients.

Inclusion Criteria: 1. Signed informed consent prior to trial participation. 2. HIV-1 infected males or females \>= 18 years of age. 3. No previous ARV therapy. 4. Any CD4+ T lymphocyte count \< 500 cells / µl. 5. HIV-1 viral load \>= 5000 copies/mL at screening. 6. Screening laboratory values that indicate adequate baseline organ function. 7. A prior AIDS defining event is acceptable as long as it has resolved or the subject has been on stable treatment (e.g. opportunistic infection; no ARV) for at least 2 weeks before screening Exclusion criteria: 1. Female patients of child-bearing potential who: * have a positive serum pregnancy test at screening or during the study, * are breast feeding, * are planning to become pregnant 2. Use of investigational medications within 30 days before study entry or during the trial