How to Fix PC Not Starting: Step-by-Step

Quick Answer

If your PC won't start, work through power, display, and POST in order. Most no-boot issues come down to a loose cable, a dead PSU, faulty RAM, or a CMOS that needs a reset. This guide walks through each step so you can isolate the fault without guessing or replacing parts unnecessarily.

Step 1: Confirm It's Actually Power, Not Display

Before anything else, check whether the PC is genuinely off or just not showing video. Listen for fans, watch for motherboard LEDs, and check your case power button connection on the front panel header. If fans spin and lights come on but you get no signal, the issue is GPU, monitor cable, or BIOS related, not power. If absolutely nothing happens, move to the PSU. With Eskom voltage swings and grid trips during loadshedding recovery, a UPS or surge protector saves a lot of dead boards over the long run. Always plug the PC into a surge-protected line or a 1500VA UPS to ride out spikes when power returns.

Step 2: Test the PSU and Wall Power

Swap to a known-good wall socket. Try a different IEC kettle cord, since these die more often than people think. If you have a spare PSU or a paperclip jumper, test the existing PSU's 24-pin start signal. A clicking noise from the PSU usually means a short or a failed capacitor. Reseat the 24-pin and 8-pin EPS connectors firmly; even slightly loose CPU power is one of the most common no-POST causes in SA where we move PCs around for LAN events. Check that the PSU's main switch on the rear is set to On and that the voltage selector, if your unit has one, is on 230V.

Step 3: Reseat RAM, GPU and CMOS Reset

Turn off the PSU at the back, hold the power button for 10 seconds to drain caps, then open the case. Pull each RAM stick, blow out the slots gently, and reseat firmly until both side clips snap. Try booting with a single stick in slot A2. If still no POST, reseat the GPU and try the motherboard's HDMI/DisplayPort if the CPU has integrated graphics. Finally, do a CMOS reset using the jumper or by pulling the coin cell battery for 60 seconds. This clears bad overclocks and corrupted BIOS settings. After a CMOS reset, expect the first boot to take 30-60 seconds while DDR5 retrains its timings.

Step 4: Check Debug LEDs and POST Codes

Modern motherboards have CPU, DRAM, VGA, and BOOT debug LEDs near the 24-pin connector. A stuck CPU LED usually means CPU power, a bent socket pin, or a dead chip. DRAM LED means a memory issue, retest with one stick. VGA means GPU not detected. BOOT means it's POSTing but can't find the OS drive. If you have a POST code display, look up the code in your motherboard manual. SA loadshedding can also corrupt boot drives, so a UPS protects against repeat trips to this guide. If the BOOT LED is the culprit, check your NVMe is fully seated and the SATA cable on any backup drive is firmly attached at both ends.

Step 5: Strip Down and Bench Test

If you've worked through the first four steps without progress, take everything out of the case and assemble on the box the motherboard came in. Connect only the CPU, one RAM stick in A2, a known-good GPU or use integrated graphics, the PSU, and a monitor. If it POSTs on the bench, the issue was a short to the case, a bad standoff, or a loose front panel header. Reassemble piece by piece, testing at each stage to catch the offending component or contact point. SA delivery from Evetech on replacement PSUs, RAM, and motherboards usually arrives in 2-3 working days with local warranty backing the swap.

Frequently Asked Questions

How do I fix a PC that won't start at all?

Work through power first: wall socket, kettle cord, PSU switch, then 24-pin and 8-pin reseats. Then move to RAM, GPU, and a CMOS reset. Most no-boot issues resolve in these four steps, and you don't need any specialised tools beyond a Phillips screwdriver.

What are common mistakes when troubleshooting a dead PC?

The biggest ones are panicking and replacing parts before isolating the fault, forgetting to drain caps before reseating, and missing the CPU 8-pin EPS connector entirely. Slow down, check debug LEDs, and only replace a component once you've ruled out cables and reseats.

Do SA users need any special tools or parts?

A magnetic Phillips screwdriver, an anti-static wrist strap, and a known-good kettle cord cover 95 percent of cases. A spare PSU or PSU tester is the next step. Evetech stocks all of these locally with same-week SA delivery and matching loadshedding-friendly UPS units.