A computer receives input from devices like keyboards and mice, processes data using the central processing unit (CPU), and outputs results through devices like monitors and printers. The main internal computer components are the CPU, random access memory (RAM), hard disk drive, motherboard, read-only memory (ROM) containing the basic input/output system (BIOS), sound and video cards, and a network adapter. The CPU acts as the computer's brain to process instructions and signals, RAM temporarily stores data for quick CPU access, and the hard disk drive provides permanent storage. The motherboard connects and powers the components to allow communication.