This video tutorial provides a simplified introduction to computer systems for beginners. It defines a computer as a programmable electronics device that processes input data and presents the output to the user. Computer systems consist of hardware components (physical parts like keyboard, monitor, etc.) and software components (application and system software). The operating system is crucial for managing hardware components. The computer system functions through four major units: input unit (accepts data from devices like keyboard and mouse), memory unit (stores data and program instructions), central processing unit (CPU, performs processing tasks), and output unit. Each unit plays a specific role in the computer's operation.