What process is used to start a computer?

The process used to start a computer is known as booting. This refers to the sequence of events that occur when a computer is turned on and begins its initialization process. During booting, the system's firmware or BIOS (Basic Input/Output System) performs hardware checks and initializes components, followed by loading the operating system into memory to prepare the system for user interaction.

This process is distinct from shutting down, which is the procedure to power off a computer, and rebooting, which refers to restarting an already running computer. Logging in, on the other hand, is the action performed by the user to access their account after the operating system has loaded. Therefore, booting is the foundational step that starts the entire computing process, making it the correct answer.