The internal mechanisms of a quantum computer are, similarly, in many states at the same time. A quantum computer can take many inputs, do many calculations, and produce many results at the same time. So, while a normal computer can take exactly one input with N bits, a quantum computer can take inputs, simultaneously, with N qbits. But, a quantum computer is more than just a lot of normal computers running in parallel. Quantum interference is the means by which a quantum computer does its computations (the quantum part anyway).