A system and method for the processing of nucleic acids containing fluids involving manipulation of magnetically responsive particles contained therein are disclosed. In the system, a holder holds a plurality of containers containing the fluids, a heating device applies thermal energy to the fluids for incubation, and a separating device magnetically separates the particles. The heating and separating devices move into at least one operative position for processing the fluids and at least one inoperative position with respect to the containers, in which the containers are kept stationary at least during and in-between incubating the fluids and manipulating the magnetically responsive particles.