CarefulAbout 30 minutesBoth

It powers on for three seconds, then dies

Why does my laptop turn on, the fans spin, then it turns off after 3 seconds?

CF

Written by The CommonFixes team · fact checked by CommonFixes review desk

Last updated

Short answer

The machine is failing its own start up self test. Before anything appears on screen, the board checks memory, power and the processor. If one of those checks fails, it cuts power straight away rather than carrying on. Loose memory, a flat internal power state and a swollen battery are the three usual reasons, and all three are testable at home. The quickest thing to try first: do a hard power drain — Unplug the charger, and if the battery is removable take it out. Hold the power button down for thirty full seconds. Plug the charger back in without the battery, if yours comes out, and press power. This clears the stored charge that keeps a board in a failed state and it fixes a surprising number of these. Most people are done in about 30 minutes.

Full walkthrough below: 6 steps for Windows and Mac, rated careful.

Sounds like this

  • Lights come on and the fan gives a short spin
  • Everything shuts off after two or three seconds
  • The screen never shows the maker logo

Why it happens

The machine is failing its own start up self test. Before anything appears on screen, the board checks memory, power and the processor. If one of those checks fails, it cuts power straight away rather than carrying on. Loose memory, a flat internal power state and a swollen battery are the three usual reasons, and all three are testable at home.

Work through these in order

0% done
  1. 1

    Do a hard power drain

    Unplug the charger, and if the battery is removable take it out. Hold the power button down for thirty full seconds. Plug the charger back in without the battery, if yours comes out, and press power. This clears the stored charge that keeps a board in a failed state and it fixes a surprising number of these.

  2. 2

    Test with the charger only, then the battery only

    If it starts on the charger alone but dies with the battery in, the battery is the fault. A cell that has swollen or lost a cell will pull the whole machine down at start up. Stop using a swollen battery, since it is a fire risk, and replace it.

  3. 3

    Reseat the memory

    Switch off, unplug, remove the bottom cover and find the memory sticks. Push the metal clips outwards, lift each stick out, and press it back in firmly at an angle until both clips click. If there are two sticks, try starting with one at a time in the first slot. Bad contact on memory is the most common cause of an instant shutdown.

  4. 4

    Listen and watch for a pattern

    Count any beeps or watch the caps lock light. Most makers flash a code, for example three blinks for memory on many Dell and HP models. Type the pattern and your model number into the maker support site to be told exactly which part failed.

  5. 5

    Unplug anything that was added recently

    Remove a newly fitted drive, memory upgrade, wireless card, docking station or USB device and try again with nothing attached but the charger. A part that does not match the board or is not seated fully will stop the self test dead.

  6. 6

    Check for heat protection kicking in

    If the heatsink was recently removed or the laptop is thick with dust, the processor may be reporting an impossible temperature and the board shuts down to protect it. Blow the vents clear with compressed air, and if the cooler was reinstalled, make sure all screws are tightened evenly in the order printed on the metal.

If none of that worked

If it still cuts out with only the charger, one stick of memory and nothing else attached, the fault is on the board or in the power circuit and needs a repair shop with proper measuring tools.

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Who wrote this and how we checked it

CF

The CommonFixes team

Writer and researcher

We are a small group of people who spend our days repairing laptops and desktops for family, friends and small offices. Every guide here starts with a problem someone actually brought to us, and we only write down the steps that put the machine right.

  • Everyday repairs
  • Windows and Mac
  • Plain language
RD

CommonFixes review desk

Technical editor

Before a guide goes live, a second person walks through it on a real machine and checks each instruction against the maker's own support pages. Anything we cannot confirm is removed rather than guessed at.

  • Fact checking
  • Safety warnings
  • Source links

This guide was last updated on 15 August 2026. If a step no longer matches what you see on screen, tell us on the contact page and we will test it again.

A gentle reminder: back up anything you cannot afford to lose before major repairs. If a step ever feels risky, stop and ask a technician. There is no shame in that.