Follow the matching startup path
Power problems and Windows startup problems need different checks. Use the choices in the first step.
Step 1 of 5
In this guide
What happens when you press Power?
What happens when you press Power?
Press the physical Power button once and allow at least a minute. Watch for power or charging lights, keyboard lights, fans, sound, a manufacturer logo and any Windows loading screen. Note a brief flash followed by power loss, repeated on/off cycles, beeps or an error message. Check whether the keyboard responds to Caps Lock.
Listen for beeps. If the computer beeps when you press Power, the beep pattern tells you what the problem is. Count the beeps and note whether they are long or short. Step 4 shows how to look the pattern up.
If lights or fans appear but there is no picture, continue with our monitor and missing-display guide. If it starts but Windows won't load, see our blue screen guide.
If the computer starts and Windows loads, you can stop here.
Check the power and do a power reset
Check the power and do a power reset
Desktop
- Check the power lead is plugged in firmly at the computer and the wall, and the power board is switched on. Try a wall outlet directly.
- If there is a switch on the back, set it to I (on).
- Power reset: unplug the power lead, hold Power for 30 seconds, plug it back in and press Power once.
Laptop
- Plug the charger in firmly and check the charging light. Leave it charging for 15 minutes.
- Power reset: unplug the charger (and remove the battery if it is designed to come out), hold Power for 30 seconds, plug the charger back in and press Power once.
Check the lead, charger and power button
- Look for fraying, cuts, bent plugs or scorch marks. Stop using a damaged lead or charger, and only use a replacement that is compatible with your computer.
- Press the power button: it should click and spring back. If it feels stuck, loose or doesn't click, the button may be faulty.
If the computer starts and Windows loads, you can stop here.
Disconnect everything but the essentials
Disconnect everything but the essentials
- Strip down to the bare minimum: unplug every external device except the power cable, one monitor, a keyboard and a mouse. A faulty external hard drive, USB hub, printer or webcam can short and make the motherboard refuse to start as a safety precaution.
- Test accessories one by one: if the computer turns on after stripping it down, shut it down normally, plug in one device and turn it back on. Repeat until you find the exact accessory causing the problem.
If the computer starts and Windows loads, you can stop here.
Look up the beeps or blinking lights
Look up the beeps or blinking lights
Beeps and blinking lights at startup are the computer's way of telling you what is wrong, such as a memory, graphics or power fault.
On the next start, listen for beeps and watch power and keyboard indicators for a repeating pattern. Write down the sequence and any displayed error code.
Use the manufacturer's official support website with the exact computer model. Search for computer manufacturer model beep code or computer manufacturer model blinking power light, replacing those words with your make and model. Code meanings differ between manufacturers.
If the computer starts and Windows loads, you can stop here.
Look for the standby power light (SB_PWR) on a desktop
Look for the standby power light (SB_PWR) on a desktop
- What it is: most modern motherboards have a tiny, solid LED light (often green, red or amber) that turns on the moment the power supply is plugged into the wall and switched on.
- What it means: if you see this light, the motherboard is not completely dead. It is receiving basic standby power from the power supply. The problem is likely the physical power button, a short circuit in a component, or a failure to POST (the Power On Self Test).
- If there is no light at all: if the wall outlet works and the power supply switch is on but there are no lights anywhere on the board, either the power supply is dead or the motherboard has suffered a total electrical failure.
If the computer starts and Windows loads, you can stop here.
Book IT supportFrequently asked questions
Are running fans proof that Windows has started?
No. Lights and fans are observations at startup; they do not confirm that Windows loaded. If there is no picture, use the linked display guide.
Can I try a spare laptop charger?
Only compare one known to suit that laptop. A different voltage, power rating or connector needs approval from the computer manufacturer. Stop using damaged chargers.
Do beep codes mean the same thing on every computer?
No. Match the pattern to the exact make and model on its official support website, then contact us with the result.
Who should help with a faulty battery under warranty?
Take a suspected battery or charging-port fault covered by warranty to the laptop manufacturer. For other startup problems described here, contact us.
