Computers · Repair guide

How to fix a computer that won't turn on

9 fixes, easiest first4 min readUpdated November 2026

Quick fix

Plug the computer straight into a wall outlet you know works, unplug everything else, then drain leftover power by unplugging it (and removing the battery if it comes out) and holding the power button for 15-20 seconds before trying again.

What it means

When a computer won't turn on, either no power is reaching it, or it powers on (lights or fans) but never gets to Windows. No lights at all usually points to the outlet, cable, charger or battery; lights with a black screen usually points to the display, a stuck startup or a hardware fault.

Common causes

  • No power from the outlet, power strip, cable or laptop charger
  • A flat or failing laptop battery
  • Leftover electrical charge or a stuck state after a power cut
  • The PC is on but the monitor, cable or screen shows nothing
  • A USB device or disc that stops the PC from starting
  • Windows fails to load after an update or crash
  • A failed part such as the power supply, memory or motherboard

How to fix it

Work down the list. Each fix is safe to try before moving on to the next.

01Check the outlet, cable and chargerEasy

  1. Plug a lamp or phone charger into the same outlet to prove the outlet works.
  2. Plug the computer directly into the wall instead of a power strip or surge protector.
  3. Desktop: check the power cable is pushed in firmly at both ends, and that any switch on the back of the power supply is on.
  4. Laptop: check the charger is firmly connected at the wall, the brick and the laptop, and look for a light on the charger or near the charging port.
  5. Look for damage such as bent pins, frayed cables or a hot or swollen charger; stop using a damaged charger.

Why it helps: A dead outlet, switched-off power strip or loose cable is the most common reason nothing happens.

02Charge the laptop and press the power button properlyEasy

  1. Leave the laptop plugged in for a while before trying again, since a fully drained battery may need some charge first.
  2. Press the power button firmly once; on some laptops you need to hold it for a second or two.
  3. If the laptop has a battery you can remove, take it out and try to start the laptop on the charger alone.

Why it helps: A completely flat or faulty battery can stop a laptop starting even when it is plugged in.

03Unplug every extra deviceEasy

  1. Shut the PC off, then unplug USB drives, printers, docks, card readers, game controllers and external hard drives.
  2. Remove any disc from the drive and any memory card from the card slot.
  3. Leave only the power cable, keyboard, mouse and monitor connected.
  4. Try to turn the computer on. If it starts, reconnect devices one at a time to find the one causing trouble.

Why it helps: A faulty accessory or a bootable USB drive can stop the PC from powering up or reaching Windows.

04Drain leftover power (hard reset)Easy

  1. Turn the computer off and unplug the power cable or laptop charger.
  2. If the laptop battery comes out without tools, remove it.
  3. Press and hold the power button for 15-20 seconds, then let go.
  4. Reconnect the battery and power, then press the power button.

Why it helps: Draining leftover charge clears a stuck power state, which is common after a power cut or storm.

05If lights come on but the screen stays black, check the displayEasy

  1. Desktop: make sure the monitor is switched on, plugged in and set to the right input, such as HDMI or DisplayPort.
  2. Desktop: plug the monitor cable into the graphics card ports if the PC has them, not only the motherboard ports.
  3. Laptop: turn the screen brightness up, or connect an external monitor or TV to see whether a picture appears there.
  4. Press Windows + Ctrl + Shift + B to reset the graphics driver; a beep or a flicker means Windows is running.
  5. If the laptop works on an external monitor, the built-in screen or its cable may be faulty.

Why it helps: Many PCs that seem dead are actually running with nothing shown on the screen.

06Note any beeps or blinking lightsEasy

  1. Turn the computer on and listen for beeps, and watch the power or caps lock light for a blinking pattern.
  2. Count the beeps or blinks and write down the pattern.
  3. Look up the pattern in your computer's user manual or on your PC maker's support site.
  4. Patterns often point to memory or motherboard problems, which helps a repair shop or the maker fix it faster.

Why it helps: Beep and light codes are the computer's way of naming the part that failed.

07Run your PC maker's built-in hardware testMedium

  1. If you have a Dell: turn the PC on and press F12 repeatedly at the Dell logo, then choose Diagnostics from the one-time boot menu.
  2. If you have an HP: hold the power button for at least five seconds to turn it off, turn it on and press Esc about once a second, then press F2 to open HP PC Hardware Diagnostics UEFI. Choose System Tests > Fast Test.
  3. If you have a Lenovo ThinkPad: connect the charger, turn it on and press F10 right away to open UEFI Diagnostics. For other Lenovo models, open the Lenovo Vantage app and choose Hardware scan if Windows still starts, or check your model's user guide.
  4. Other brands: check your PC maker's support site for its built-in test.
  5. If a test fails, write down the error code or failure ID and contact the maker's support.

Why it helps: The maker's test runs before Windows loads and can confirm whether memory, the drive or another part has failed.

08If it powers on but Windows won't load, use Startup RepairMedium

  1. Turn the PC on, then hold the power button to switch it off before Windows finishes loading. Do this two times.
  2. On the third start, Windows should show the Automatic Repair screen. Select Advanced options.
  3. Select Troubleshoot > Advanced options > Startup Repair and follow the prompts.
  4. If the problem began after an update, choose Troubleshoot > Advanced options > Uninstall Updates instead and remove the latest quality update.
  5. Uninstalling an update keeps your personal files, but some updates cannot be removed. If you have a recent backup, keep it handy before changing anything.
  6. If asked for a BitLocker recovery key, find it in your Microsoft account on another device before continuing.

Why it helps: Startup Repair fixes common problems that stop Windows from loading even though the hardware powers on.

09Reseat the memory (desktops only, with care)AdvancedHands-on

  1. Warning: only do this if you are comfortable opening the side panel, and if the PC is out of warranty or the maker allows it. Otherwise, take it to a repair shop.
  2. Shut down, switch off the power supply, unplug the power cable and hold the power button for 15 seconds.
  3. Touch a bare metal part of the case to discharge static before touching anything inside.
  4. Open the clips at the ends of each memory stick, pull it straight out, then push it firmly back in until the clips snap shut.
  5. Close the case, reconnect power and try again. Do not open laptops or the power supply itself.

Why it helps: A memory stick that has worked loose after a move or bump can stop a desktop from starting.

Check it's fixed

  • The power light comes on and the fans spin when you press the power button.
  • You see the maker's logo, then the Windows sign-in screen.
  • The computer starts normally again after a full shut down from Start > Power > Shut down.

When to get help

If there are still no lights after trying another outlet and charger, or a hardware test reports a failure, contact your PC maker or a repair shop, since the power supply, battery or motherboard may need replacing. Do not open a laptop or a power supply yourself.

Questions

Why won't my computer turn on after a power outage?

A surge or sudden cut can leave the PC in a stuck power state or damage the power supply. Plug it straight into a working outlet and drain leftover power by holding the power button for 15-20 seconds while it is unplugged.

My laptop's charging light is on but it won't turn on. What does that mean?

Power is reaching the laptop, so the problem is more likely the display, a stuck startup or a hardware fault. Try an external monitor, a hard reset and the maker's built-in hardware test.

Can a Windows update stop my computer from turning on?

An update can stop Windows from loading, but it cannot stop the power light and fans from coming on. If the PC powers on but stops before Windows, use Startup Repair or uninstall the latest update from the recovery screen.

Will I lose my files if my computer won't turn on?

Usually not. Files are stored on the drive, which is often fine even when another part fails. A repair shop can usually copy them off if the PC cannot be fixed.

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