can a computer work without an Operating System? if yes, how?
An operating system provides an interface between the hardware and user. It provides management and coordination of activities and the sharing of the resources of the computer and acts as a host for programs run on the machine. As a host, it handles the details of the operation of the hardware, relieving application programs from having to manage these details and thereby making it much much easier to write programs.
Almost all computers (including portable media players, handheld devices, video game consoles, robots, domestic appliances like dishwashers or washing machines) use an operating system of some type.
In theory, a computer could work without an Operating System - each program will have to have its own code for handling the hardware, management and coordination of activities and sharing of the resources of the computer. In practice, this makes writing programs so very hard that it remains just theory.