What happens when a computer cannot find a boot device?

When a computer cannot find a boot device, a boot error occurs. This typically manifests as a message on the screen indicating that the system is unable to locate the operating system. During the boot process, the computer's BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface) searches for devices that contain bootable media, such as hard drives, SSDs, USB drives, or optical drives. If no valid bootable device is found, the system generates an error to inform the user that it cannot proceed with starting up the operating system.

The other scenarios, such as the system shutting down, automatic updates of the BIOS, or software installation proceeding, do not apply in this situation. The system typically remains powered on and in a standby state, waiting for user intervention or further diagnosis. Boot errors signal the need for troubleshooting to identify any issues related to hardware connections or configurations.