If you receive the “Non-system disk or disk error” error message, what issue should you start troubleshooting for?

A.
A missing operating system where the computer failed to locate a boot sector with an operating system installed.

B.
A memory size error.

C.
A missing or malfunctioning keyboard.

D.
None of the above

Explanation:
You have a missing operating system when the computer fails to locate a boot sector with an operating system installed on any of its disks.
Incorrect Answers
B: The power on self-test (POST), built into a computer, indicates memory specific issues with a number commencing with 2.
C: The power on self-test (POST), built into a computer, indicates missing or malfunctioning keyboard issues with a number commencing with 3.
D: A missing operating system is the correct answer.
References:
David Groth and Dan Newland, A+ Study Guide, 2nd Edition, Alameda, Sybex, 2004, p.777.
James G. Jones, Craig Landes, A+ Exam Cram, 2nd Edition, Que Publishing, Indianapolis, 2003, Chapter 16