A computer that doesn't start at all — no fans spinning, no lights, no beeps, nothing — is usually a power problem, not a dead machine. That's good news, because power problems are the ones you can check safely yourself, and the fixes are usually free.

The key distinction: dead (nothing happens when you press the button) is different from turns on but no display (fans spin but the screen is black). This page is about the fully-dead case. If your fans do spin, see Computer turns on but no display.

Before you start

  • Don't open the case yet. Power problems are 90% of these faults and none of them need the case open.
  • Know your machine: is it a desktop or a laptop? A laptop "won't start" is usually the battery or the charger, and has its own checks. These steps assume a desktop first, with laptop notes at the end.
  • Never open a power supply. There's a large capacitor inside that can hold a charge long after the PC is off. Power-supply faults are a technician job, not a home repair.

Fix 1 — Check the wall and the strip

This sounds obvious but it's the single most common cause. Make sure:

  • The wall socket works (plug a phone charger or a lamp in to test it).
  • If there's a power strip, extension lead, or surge protector, it's switched on and not tripped.
  • There's no RCD / GFCI outlet that's tripped (common in kitchens and bathrooms) — press its reset button.

If the socket is dead, that's your problem, not the PC's.

Fix 2 — Check the power cable and the PSU switch

  • Make sure the power cable from the wall is plugged firmly into the back of the PC. Unplug and replug it.
  • If you have a spare cable, swap it. Cables fail silently.
  • Look at the back of the power supply for a little I/0 switch. Many people leave it on 0 (off) and wonder why the PC won't start. Set it to I (on) and try again.
  • If your power supply uses a C13/C14 cable (the common PC power lead), make sure it's fully seated in the supply's socket — these can look plugged in but be out a few millimetres.

Fix 3 — Rule out a front-panel button fault

Rare, but worth 30 seconds: the power button on the case can fail. If everything above is solid, the button itself may not be triggering the start. A technician can usually test this, or it can be bypassed with a screwdriver on the motherboard header (a technician job, not a guess).

Fix 4 — The power supply itself

If the socket, cable, and switch are all good and the PC is still completely dead, the power supply (PSU) is the most likely culprit. Signs:

  • You hear the fans spin briefly then stop, or nothing at all.
  • The PC sometimes starts, then dies.
  • A burnt smell near the back of the case (unplug immediately — that's a hardware fault, stop and get it looked at).

A failing PSU is a replace job. It's one of the cheaper parts and a standard technician repair, but you don't do it yourself unless you're comfortable working inside a PC.

Advanced / when to get help

If you've confirmed the wall, cable, and PSU switch are all fine, the fault is most likely the power supply or, less commonly, the motherboard or CPU. These are technician jobs. Before paying for one:

  • Note the exact symptoms (nothing happens / fans spin then stop / beeps / lights) — that tells the technician which part to test.
  • Check your warranty — a dead PC that's within warranty is often a free or cheap power-supply swap.
  • A reputable local technician can usually test the PSU and motherboard with a power-supply tester and a multimeter in under an hour.

Laptop notes

For a laptop that won't start, the usual suspects are the charger and the battery:

  • Try a different charger if you have one.
  • Plug it in, wait 10–15 minutes (a fully drained battery needs time to take a charge), then press the power button.
  • Look for a charging LED — no LED at all usually means the charger or the battery, not the whole machine.
  • Laptops with a removable battery: remove the battery, plug in the charger, and try to power on from the charger alone. If it starts, the battery is the problem.

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