A computer can perform inputting, processing and cotrolling but it can't perform understanding as it is has no brain. It can't earn from its previous experiances.
A computer system consists of two major elements: hardware and software. Computer hardware is the collection of all the parts you can physically touch. Computer software, on the other hand, is not something you can touch. Software is a set of instructions for a computer to perform specific operations. You need both hardware and software for a computer system to work.