You press the power button and nothing happens. Or the fans spin for a second and then stop. Or the system powers on but the screen stays black. Few things cause as much immediate panic as a PC that won't turn on — especially if you have work deadlines or unsaved files you're worried about.
The good news: most of the time, a PC that won't turn on has a fixable, relatively inexpensive cause. In Nigeria, power-related issues account for the majority of these cases. Work through this guide systematically before drawing any conclusions.
Step 1: Check the Power Source
This sounds obvious, but start here — power issues cause the majority of "PC won't turn on" situations in Nigeria.
- Is your UPS or surge protector on? Check the power indicator.
- Is there actually power in your house? Try a lamp or phone charger in the same socket.
- Is your UPS battery dead? A UPS with a failed battery provides no output even if it seems to be on.
- Is the power cable fully seated in both the wall socket and the PC's power socket?
- Is the power switch on the back of the PC's PSU set to ON (marked with |, not O)?
Step 2: Listen and Look Carefully
When you press the power button, what happens? Each scenario points to a different cause:
- Nothing at all — no lights, no fans: Power is not reaching the system. PSU or power source issue.
- Fans spin briefly then stop: System is trying to POST but failing. Could be RAM, CPU, or motherboard.
- Fans spin, PC seems to run, but no display: The system is running but the display chain has failed. GPU, monitor, or cable issue.
- Beep codes: If you hear beeps (not all motherboards have speakers), count them. They are error codes that point to specific failures.
- Lights come on, everything spins, but Windows doesn't load: Storage or OS issue.
Step 3: Check the PSU
The power supply unit is the most common single point of failure in Nigerian PCs, especially after a power surge. There's a simple test called the "paperclip test" (look it up) that can tell you whether a PSU is producing power, but this requires care — only attempt it if you're comfortable with hardware. A safer approach is to try a known-working PSU from another machine, or bring it to a technician for a quick test.
Signs of a failed PSU: burning smell from the rear of the PC, the PC won't respond at all even with confirmed power at the wall, or the PSU fan doesn't spin at all when you press power.
Step 4: Reseat Your RAM
Loose or slightly unseated RAM is one of the most common causes of a PC that won't POST. Open the case, press the release tabs on each RAM stick, and remove them. Inspect the gold contacts for dust or oxidation. Reinsert firmly until you hear both clips click. Try booting with one stick at a time if you have two sticks — this isolates a faulty stick.
Step 5: Check the Monitor and Display Connection
If the PC seems to be running (fans spin, lights are on) but the screen is black:
- Is the monitor power cable plugged in and the monitor on?
- Is the HDMI or DisplayPort cable fully seated at both ends?
- Try a different cable — HDMI cables can fail suddenly.
- If you have a GPU, are you plugging into the GPU outputs, not the motherboard outputs? (The correct ports are on the GPU, lower in the case.)
- Try a different monitor or TV if possible.
Step 6: Disconnect Non-Essential Hardware
Unplug everything except the CPU, one stick of RAM, and the boot drive. Remove the GPU if you have CPU integrated graphics. Remove all USB devices. Try booting in this minimal configuration. If it boots, add components back one at a time to find the culprit.
Step 7: Check the CMOS Battery
The small coin-cell battery on your motherboard (a CR2032, about the size of a ₦50 coin) powers the BIOS settings when the PC is off. If this battery is dead — they typically last 5–7 years — the motherboard may refuse to POST or lose settings every time. Replace it (costs under ₦1,000) and see if this resolves the issue.
Step 8: Inspect for Physical Damage
Look inside the case with a torch. Are there any capacitors on the motherboard that look swollen or have brown residue around them? Any signs of burning (black marks, burnt smell)? Any cables that look melted or crimped? Generator exhaust and power surges can cause this kind of damage.
When to Stop DIY and Get Help
If you've worked through all the steps above and the PC still won't turn on, you're likely dealing with a failed motherboard, CPU, or combination of components. At this point, further DIY risks making things worse. A professional diagnosis can quickly identify which component(s) failed using proper test equipment.
In Nigeria, post-surge failures often involve the PSU having died while protecting the motherboard — meaning the motherboard is fine and only needs a PSU replacement. A good technician can confirm this quickly. The diagnostic is almost always worth it before spending money on replacement parts.