- The power supply sends electricity to the components of the computer, such as the motherboard, hard drive, and fans.
- The BIOS (basic input/output system) initializes and performs a power-on self-test (POST), which checks the essential hardware components to ensure they work correctly. If any issues are detected, error messages may be displayed.
- The operating system (OS), such as Windows or macOS, is loaded from the hard drive or another storage device into the computer’s RAM (random access memory).
- The OS then initializes its own components and drivers and presents the login screen or desktop environment to the user.
