Complete Won't Turn On Diagnostic

Quick Answer

A PC that won't turn on usually has a power, RAM or motherboard issue you can diagnose in under 30 minutes with no special tools. Work through PSU, power button, RAM reseat, CMOS reset, and GPU reseat in that order. Most SA users find the fault before reaching the motherboard step.

Step 1 to 4: Power and Cables

Confirm the wall socket works by plugging in a phone charger or kettle. Flip the PSU's I/O switch to ON (it's surprisingly easy to knock off when reaching behind the case). Check that the 24-pin ATX cable and the 8-pin EPS CPU cable are fully seated, push them in until you hear a click. If you have a spare PSU or a friend's, swap it in to rule out a dead unit. Roughly 40 percent of "won't turn on" cases in SA are PSU-related, especially after load-shedding voltage spikes.

Step 5 to 8: RAM, GPU and CMOS Reset

With the PC unplugged, remove all RAM sticks, blow out the slots, and reseat one stick in slot A2 only. Try booting. If nothing, try the other stick in the same slot. Next pull the GPU and reseat it firmly into the PCIe slot, ensuring the latch clicks and the 8-pin or 16-pin power cable is plugged in. Finally, do a CMOS reset by removing the silver coin battery on the motherboard for 60 seconds (or use the CLR_CMOS jumper). This wipes any bad BIOS settings that can prevent POST.

Step 9 to 10: Front Panel and Last Resort Tests

The power button itself can fail. Locate the front panel header on the motherboard (usually bottom right) and short the two PWR_SW pins with a screwdriver tip for a second. If the PC powers on, your case button or its cable is the issue. If POST still fails, try outside the case on the motherboard box (a "bench test") to rule out grounding shorts from a loose case screw. At this stage, if there's no fan spin or LED activity at all, the motherboard or CPU is the likely culprit and a trip to a local technician is warranted.

Frequently Asked Questions

What's the most common reason a PC won't turn on after load-shedding?

PSU damage from voltage spikes when power returns. A surge protector or UPS would have prevented it. Replace the PSU first before assuming the motherboard is dead.

Do I need to buy parts before diagnosing?

No, every step above uses what's already in your case. You only need replacement parts after isolating the fault. Evetech stocks PSUs, RAM and motherboards for nationwide delivery once you know what failed.

Can I damage anything by trying these steps?

Not if you unplug the PC, touch the case to discharge static, and don't force connectors. CMOS resets, RAM reseats and cable checks are completely safe even for first-time builders.