A server lost power and will not reboot. The KVM indicates the OS cannot be found. Which of the following actions should an administrator take to fix this issue?

After a power failure, the CMOS battery may have failed or settings may have been reset, causing the BIOS to look for a boot device in the wrong order - for example, trying to boot from a network adapter or empty optical drive before the OS disk. Correcting the boot order in BIOS to point to the system drive resolves the 'OS not found' error without data loss.

Reloading the OS from DVD is a destructive, last-resort action that destroys existing data and is inappropriate before first verifying whether the OS disk is simply not targeted by the boot sequence.

Restoring the OS from backup is a major recovery operation that should only be pursued after confirming the OS itself is actually corrupted or missing, not merely unreachable due to boot order.

Confirming the partition is marked active addresses MBR-level boot configuration but is a more complex step that comes after the simpler BIOS boot order check has been ruled out.