The answer is that the front panel power switch header is not connected correctly. This is the most likely cause when a PC won't power on after a motherboard replacement because the power button on the case completes a simple circuit on the motherboard’s front panel header; if that tiny two-pin connector is misaligned or unplugged, the motherboard never receives the signal to start the power supply, which explains why the PSU fan doesn’t spin and no LEDs light up. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of the power-on sequence and the importance of front panel connectors, often appearing as a common trap where technicians assume a dead PSU or shorted board. A reliable memory tip is to think of the power switch header as the “ignition key”—without it properly seated, the system has no way to turn on, so always double-check the small, often unlabeled pins against the motherboard manual.
220-1101 Core PC Hardware Troubleshooting Practice Question
This 220-1201 practice question tests your understanding of core pc hardware troubleshooting. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
After replacing a motherboard, a technician finds that the PC will not power on at all. The power supply fan does not spin, and no LEDs light up. The PSU was working before the replacement. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The front panel power switch header is not connected correctly
No power at all after a motherboard swap strongly suggests an electrical connection issue. The most common cause is that the front panel power switch header is not connected correctly to the motherboard, or the PSU is not properly connected to the motherboard.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 power supply is dead
Why it's wrong here
While possible, it is less likely than a connection issue since the PSU was working before the swap.
✗
The CPU is not compatible with the new motherboard
Why it's wrong here
An incompatible CPU would prevent POST but usually still allows the PSU fan to spin briefly.
✓
The front panel power switch header is not connected correctly
Why this is correct
If the power button is not connected to the correct pins, pressing it will not complete the circuit to start the PSU.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
The RAM is not seated properly
Why it's wrong here
Improper RAM seating causes beep codes or no display, but the system typically still powers on (fans spin).
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 220-1201 question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Core PC Hardware Troubleshooting — This question tests Core PC Hardware Troubleshooting — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The front panel power switch header is not connected correctly — No power at all after a motherboard swap strongly suggests an electrical connection issue. The most common cause is that the front panel power switch header is not connected correctly to the motherboard, or the PSU is not properly connected to the motherboard.
What should I do if I get this 220-1201 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 220-1201 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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