Patients will be randomized to adefovir dipivoxil with nelfinavir and saquinavir or adefovir dipivoxil with nelfinavir or saquinavir plus a nucleoside analog (zidovudine, lamivudine, or stavudine). Within each treatment arm, patients will be randomized to 1 of 2 doses of adefovir dipivoxil in a blinded manner. Patients randomized to receive a nucleoside analog will then be assigned to receive either zidovudine, lamivudine, or stavudine based upon their previous RTI therapy. A daily dose of L-carnitine will be administered to all patients.