How to inspect a used laptop before buying

Write down exactly what you need: the processor generation (for example, 8th generation Intel or newer), RAM, SSD size, screen size and any must-haves such as a backlit keyboard. "Core i5" on its own tells you very little. A ten-year-old i5 and a recent one are very different machines.

Bring a USB flash drive, earphones and your phone for a hotspot. Ask the dealer to have the laptop charged and to bring its charger. If it's a MacBook or a recent Windows laptop, ask them to have it signed out of any accounts.

Many UK-used laptops were company machines. Most were properly released, but some still carry locks that stop you using them fully.

• Restart the laptop and open the BIOS or UEFI setup (usually by pressing F2, F10, F1, Esc or Delete as it starts). If it asks for a supervisor or administrator password, the laptop is locked. Walk away or get it cleared first.
• During Windows setup, a screen saying the device belongs to an organisation, or asking for a work account, means it's still enrolled in company management.
• On a MacBook, go through setup: a Remote Management screen means it's enrolled with a company. Activation Lock, tied to someone's Apple ID, must also be off.

If the laptop is already set up and running, you can still ask the dealer to reset it in front of you. It's the surest way to see these screens.

On Windows, open Command Prompt and type powercfg /batteryreport. It saves a report file; open it and compare Design Capacity with Full Charge Capacity. The closer they are, the healthier the battery. The report also shows a cycle count on many laptops.

On a Mac, hold Option, click the Apple menu, choose System Information and open Power. You'll see the cycle count and a condition such as Normal or Service Recommended.

A worn battery isn't a deal-breaker, since batteries can be replaced, but it should be reflected in the price. A swollen battery is a deal-breaker. If the laptop's base bulges or the trackpad feels raised, don't buy it.

• Open a text editor and press every key, including the number row, function keys and arrows. Check the backlight if it has one.
• Use the trackpad, including clicks, two-finger scrolling and the physical buttons on business laptops.
• Plug your flash drive into every USB port. Test the HDMI or display port on a screen if one is nearby, the headphone jack with your earphones, and the SD card reader if there is one.
• Charge through the charging port, and wiggle the plug gently. A loose connection is a common fault.
• Connect to your hotspot over Wi-Fi, pair Bluetooth earphones or your phone, and open the camera and microphone.

Open a plain white page full-screen and look for dead pixels, bright spots, lines and shadows. Then try a dark image. Pressure marks (pale patches from something pressing on the lid) are common on used laptops.

Open and close the lid several times. The hinges should feel firm and even, with no creaking or cracks in the plastic near them. Look under the laptop for missing screws, which can be a sign it has been opened or repaired.

Check the real specs in the system, not from the sticker on the palm rest. On Windows, open Settings › System › About for the processor and RAM, and Settings › System › Storage for the drive. On a Mac, use About This Mac.

If the dealer allows it, run a free tool such as CrystalDiskInfo from your flash drive to read the drive's SMART health. A warning or bad status means the drive may fail soon. Check that Windows is activated under Settings › System › Activation.

Play a video or open several browser tabs and leave it for a few minutes. Listen to the fan. A loud, constant fan or a very hot base can mean dust build-up or a failing cooling system. Sudden shutdowns are a serious warning sign.

For an office or a resale batch, ask for the same model throughout. It makes setup easier and means chargers and parts fit every machine. Check every unit for locks and specs, since those can differ within a batch, and at least sample the battery, screen and keyboard checks.

Agree in writing what happens to laptops that fail your checks: replacement, refund or a lower price. Record serial numbers against what you paid. Our guide to buying electronics in bulk from Lagos markets covers payments and delivery for bigger orders.

Post a buy request in the Dealrs app with the spec, condition and quantity you need. The Dealrs team finds verified dealers who have matching laptops, many in Computer Village, and gets back to you. Dealrs doesn't inspect goods, so the checks above are yours to make. See more on buying laptops and computers in bulk.