Computer won't turn on: safe checks before a repair

A black screen does not necessarily mean your files are lost.

The answer in 2 lines. Start by distinguishing no power from no picture. Check the wall socket, external power connections and monitor, then note any lights, fan noise or messages. Disconnect unnecessary accessories before trying again. Follow your model's instructions for any forced shutdown or reset: there is no universal button-hold time. Do not open a power supply or sealed battery. If the computer contains important files, avoid resets or reinstallation until you understand their effect on your data.

Start with these checks

Check that the socket is switched on and the external power leads are properly connected. Use only the correct charger or power lead, with no visible damage.
On a desktop, check the monitor's power, selected input and cable connections. A running computer with a blank monitor needs different checks from one with no lights or sound.
Disconnect unnecessary accessories and note what happens when you press the power button: lights, fan, beeps, logo or error message. Record the wording without repeatedly forcing restarts.

Stop: danger

Swollen battery or distorted case: stop charging and using the computer. Do not open, squeeze or puncture it; arrange professional assessment.
Smoke or fire: get out, stay out and call 999. Do not handle a smoking or burning computer.
Damaged power equipment: stop using it. Never open the mains power supply or charger, even after unplugging it.

What you see changes the next step

No lights or sound can indicate a power problem, but does not establish that the battery or motherboard has failed. A charger light is a clue rather than a complete test of its output.

If the computer appears to run but the screen stays blank, check the display connections and brightness. If a logo or error appears, photograph it: the computer is at least reaching part of its startup sequence.

The Imperial College London troubleshooting guide separates power, monitor and frozen-computer checks. Read the section matching your symptom and stop before any instruction you cannot apply confidently.

Keep checks outside the case

Check accessible switches and connections without removing covers. Do not try a borrowed charger merely because its plug fits: confirm that it is suitable for the exact computer.

If the machine is frozen rather than switched off, a forced shutdown may lose unsaved work. Follow the model's documented procedure instead of using a guessed button sequence. A managed work or school computer should go to its support team before recovery changes.

Repeated beeps or flashing lights can be model-specific fault codes. Record the pattern for the repairer. Avoid reseating internal parts, disconnecting sealed batteries or experimenting with internal power connections.

What not to do

Choosing a factory reset simply because the computer will not start normally.
Repeatedly powering up a machine after liquid damage, overheating or a burning smell.
Paying for replacement parts before the repairer has explained the diagnosis.

Protect your files before recovery work

A power or display fault does not by itself prove that stored files have disappeared. Recovery may be possible, but depends on the damage, storage and encryption. Tell the repairer which files matter and ask them to seek permission before erasing or replacing storage.

If the machine starts safely, use the National Cyber Security Centre backup guide: choose external storage or an online backup, copy important files and check the copy opens. Disconnect removable backup storage afterwards.

Keep recovery keys somewhere safe and accessible separately from the computer. Do not post passwords or recovery keys in public troubleshooting discussions.

Repair costs and consumer rights in England

Ask for a written quotation explaining the diagnostic charge, proposed work, parts, data handling and repair guarantee. State whether you want a repair, file recovery or both: these can involve different work.

For a purchase from a trader, your rights depend on the fault and circumstances. Guidance checked in 2026 explains a short-term right to reject qualifying faulty goods within 30 days, followed by repair or replacement rights. Read MoneyHelper's consumer-rights guide and select the section matching the time since purchase.

Contact the seller with proof of purchase and your fault description before commissioning work if you want to claim against them. For tailored next steps, answer the questions in the Citizens Advice faulty-goods tool. Its country links cover advice outside England.

Good to know

Keep laptop ventilation openings clear and use a firm surface.
Follow the battery and charger safety advice linked below; do not cover charging equipment.
Once the computer works again, arrange regular backups and check that they contain your important files.

Illustrative example: in York, Alex hears the desktop fan but sees a black screen. Checking the external connections reveals that the monitor's power lead is loose. Reconnecting it restores the picture, without changing the computer or risking a reset.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on 5 November 2026, for England. Confidence: high for external power and monitor checks, backup advice, battery precautions and consumer-rights principles; medium for interpreting symptoms. Fault codes, resets and data recovery depend on the model and damage.