hardMultiple ChoiceObjective-mapped
220-1201 Practice Question: A technician is troubleshooting a desktop PC that…
A technician is troubleshooting a desktop PC that displays a blank screen on boot. The monitor's power LED is on (green), but no image appears. The PC beeps once during startup, and the hard drive activity light flashes. Which component is most likely faulty?
⚠ Common exam trap
CompTIA often tests the distinction between a POST beep code indicating a non-fatal error (single beep) versus fatal errors (multiple beeps), leading candidates to incorrectly suspect the CPU or RAM when the video card is the actual culprit.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The video card
The single beep and hard drive activity indicate that the POST (Power-On Self-Test) has passed for the CPU and RAM, isolating the issue to the video subsystem. Since the monitor's power LED is green (receiving power) but no image appears, the most likely faulty component is the video card, which is responsible for generating the display signal.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The CPU
Why it's wrong here
A single short beep during startup typically indicates that the Power-On Self-Test (POST) has completed successfully, meaning core components like the CPU, motherboard, and basic memory have passed their initial diagnostic checks. If the CPU were faulty, the system would likely produce no beeps at all, a continuous beep, or a specific error code indicating a CPU failure, not a successful POST beep.
- ✗
The RAM
Why it's wrong here
The presence of a single beep signifies that the system's Power-On Self-Test (POST) has successfully completed its initial checks, including the integrity of the RAM. Issues with RAM typically manifest as distinct beep codes (e.g., three short beeps, or a continuous beep depending on the BIOS manufacturer) or prevent the system from booting entirely, rather than allowing a successful POST beep.
- ✓
The video card
Why this is correct
When a desktop PC emits a single beep, it confirms that the Power-On Self-Test (POST) has successfully initialized critical components such as the CPU, RAM, and motherboard. If the system then fails to display any image, the video card is the most probable culprit. This could be due to a faulty card, improper seating in its expansion slot, or a damaged video cable preventing signal transmission to the monitor.
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The monitor's power supply
Why it's wrong here
The monitor's power supply is unlikely to be the issue because the power LED on the monitor is illuminated. A lit power LED explicitly indicates that the monitor is receiving electrical power and its internal power conversion circuitry is functioning correctly. Therefore, the absence of an image on the screen points to a problem with the video signal coming from the PC, not the monitor's power delivery.
Go deeper
Related to this question
Learn chapter
Power Supply Units and Connectors
Key term
Light-emitting Diode
A light-emitting diode (LED) is a semiconductor device that emits light when an electric current passes through it, commonly used as an indicator or illumination source in electronic devices.
Key term
CPU
The Central Processing Unit (CPU) is the main electronic brain of a computer that carries out instructions from software by performing basic arithmetic, logic, control, and input/output operations.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1201 exam.