A method, not a list of fixes
Troubleshooting questions are not asking you to memorise every possible fault. They are asking whether you can work through a problem systematically, and the marks follow the method.
The approach is the same one used in every diagnostic discipline: find out exactly what is wrong, form a theory about why, test that one theory, and only then change something. Changing several things at once is the classic beginner error, because when it works you still do not know what was broken — and if it does not, you now have three new variables.
- 1. Identify the problem. What exactly happens, and when? Ask what changed recently — new software, a new cable, a power cut.
- 2. Form a theory. What single cause would explain all the symptoms? Start with the simplest and most likely.
- 3. Test the theory. Change one thing only, so the result means something.
- 4. Fix, then verify. Confirm the original symptom has gone and that nothing else has broken.
- 5. Document. Record the fault and the fix, so the next person — or you in six months — does not start from nothing.
Check the simplest cause first
A monitor showing nothing is far more often unplugged than faulty. A printer that will not print is more often out of paper than broken. Working from the cheapest, most likely explanation upwards is not a lack of ambition — it is what keeps you from replacing a working graphics card. Examiners award marks for starting with power, cables and connections.
Is it hardware or software?
The single most useful early question, because it halves the search. Two tests usually settle it.
Does the fault survive a restart into a different environment? A problem that disappears when you boot from a USB drive is almost certainly software. Does the fault appear on other hardware? A file that fails to open on three machines is a file problem, not a machine problem.
| Symptom | Likely cause | First thing to try |
|---|---|---|
| No power at all | power supply or socket | check the cable and try another socket |
| Beeps but no display | RAM or graphics card seated badly | reseat the RAM |
| Very slow, fan loud | overheating or too little RAM | clean the fan, check memory usage |
| Random crashes | faulty RAM or overheating | run a memory test |
| Will not boot into the OS | corrupt system files or a failing disk | boot from recovery media |
| One program crashes only | that program or its data | reinstall the application |
| No network | cable, driver or configuration | check the cable, then ping the router |
Preventive maintenance
Most faults are cheaper to avoid than to diagnose, and the syllabus expects you to know the routine tasks.
On the software side: keep the operating system and applications updated so that security holes are closed, run antivirus scans, remove software no longer used, and take regular backups. On the hardware side: keep vents and fans clear of dust, since overheating causes both slowdowns and permanent damage; use a surge protector or UPS in areas with unstable power; and handle components by their edges, using an anti-static wrist strap where possible.
The 3-2-1 rule for backups
Keep three copies of anything important, on two different kinds of media, with one of them off-site. A backup sitting on the same machine as the original is not a backup — a theft, a fire or a ransomware infection takes both. This rule appears in exam answers about data loss and is worth quoting by name.
Working through a fault
Exam questions give you a scenario and ask for the steps. Write them as steps, in order, each one testing a single possibility.
A user reports that their computer turns on — fans spin, lights come on — but the monitor stays completely blank. Describe how you would diagnose the fault.
- Confirm the symptom: is the monitor's own power light on?A dark monitor with no power light is a monitor or socket problem, not a computer problem. This one question splits the search in half.
- Check the video cable at both ends, and that the correct input source is selected on the monitor.Cables and input selection are the most common causes and cost nothing to check.
- Try the monitor on a different computer, or a different monitor on this one.Swapping one component at a time is the only way to tell which of the two is at fault.
- If the monitor is fine, listen for beep codes at startup and reseat the RAM and the graphics card.Beeps are the machine reporting a fault before any display is available. Badly seated RAM is a very common cause of exactly this symptom.
- Document what was found and what fixed it.The last step is a mark in most schemes, and it is the one students omit.
Check monitor power and input, then the cable, then swap to isolate, then reseat RAM and graphics card — one change at a time.
Before you leave this chapter
- Identify → theorise → test → fix → verify → document.
- Change one thing at a time, or the result tells you nothing.
- Check power, cables and connections before suspecting a component.
- Swapping a suspect part into a known-good machine isolates the fault.
- Backups follow 3-2-1: three copies, two media, one off-site.
Narrowing it down question by question
A good first question halves the search. A bad one tells you nothing you did not already know, and you have spent time to learn it.
For each common symptom there is one cheap question that splits the possibilities cleanly in two. Asking it first is the difference between a five-minute diagnosis and an afternoon of swapping parts.
Each step is a single check that eliminates half of what is left. Notice the first question in every case costs nothing — no part is replaced until three free checks have failed.