CompTIA A+ Core 1 (220-1001) — Question 317

A user powers on a desktop computer, and the following error appears on the monitor: OS not found. The user notes there are no visual indications of an error. A reboot yields the same result. Which of the following is the MOST likely cause of the issue?

Answer options

• A. The system partition is set to active.
• B. A USB flash drive that contains offline diagnostics is plugged in.
• C. The CD-ROM drive contains a Windows setup disk.
• D. The boot order has changed.

Correct answer: D

Explanation

The correct answer is D because if the boot order has changed, the system may attempt to boot from a device that does not contain an operating system, leading to the 'OS not found' error. Option A is incorrect because the active partition is typically where the OS resides. Option B is not relevant if the system is trying to boot from a non-OS device. Option C is also incorrect as the computer would boot from the CD-ROM if it was set to do so.