What diagnostic program checks hardware readiness upon booting a PC?

The Power-On-Self-Test (POST) is a diagnostic program integral to the boot process of a PC. It executes right after the computer is powered on, serving as an initial check of the hardware components. During POST, the BIOS (Basic Input/Output System) verifies that essential hardware such as the processor, memory, and storage devices are functioning correctly and are properly connected. If any issues are detected during this process, the system may emit beep codes or display error messages to indicate the specific problem, preventing the operating system from loading until the issues are resolved.

This check is crucial as it ensures that the system is capable of operating with the installed hardware. Other options, while they may seem relevant, do not specifically correlate with this initial boot diagnostic function. For example, "post-boot verify" does not represent a recognized standard term in PC diagnostics, and "system diagnostics" typically refers to various testing utilities that run after the boot process, while "hardware integrity checker" suggests a more ongoing or comprehensive assessment rather than the initial readiness check conducted by POST.