Part 2 - Patients will take capravirine alone for 7 days. On day 1, patients will have a physical examination, urine test and laboratory blood tests. Blood samples will be collected just before the first dose of capravirine is given and again at 0.5, 1, 2, 4, 6, 8 and 12 hours after the dose. A small plastic tube will be placed in a vein to avoid multiple needle sticks. On day 8, patients will have another physical examination and laboratory blood tests. Blood samples will be drawn again as described above. Additional drugs will then be added to the regimen (in varying doses according to group), as follows: