System startup refers to the process that occurs when a computer or electronic device is powered on. During this phase, the system performs a series of checks and initializations to ensure that all hardware components, such as the CPU, RAM, and hard drive, are functioning correctly. The BIOS or UEFI firmware is responsible for these checks and then loads the operating system from the storage device. Once the operating system is loaded, it initializes system services and user interfaces, allowing users to interact with the device. This process includes loading essential drivers for hardware components, such as printers and graphics cards, enabling them to work properly. After startup, the system is ready for user commands and applications.