How to Check a Used Laptop Before Buying

Buying a used laptop is mostly a question of what you can find out in the twenty minutes you have the machine in front of you. Almost every problem worth worrying about will show itself in that time if you know where to look. This is the order worth doing it in, roughly cheapest-to-fix last.

If you have not yet decided what kind of machine you are looking for — what budget, what specification, what it needs to do — start with the complete guide to buying a used laptop and come back to this list when you have one in front of you.

Before you touch it: what is it, actually?

Ask for the exact model number and look it up on your phone. "i5 8GB" describes hundreds of different laptops from ten different years, and the difference between them is the difference between a machine that will last you three more years and one that was already slow when it was new.

The two things you want from that search are the year it was released and the processor generation. A laptop from three years ago with a mid-range processor will beat one from eight years ago with a top-end processor, almost every time.

The screen

Open a plain white image full screen, then a plain black one. On white you will see dead or stuck pixels and any yellowing. On black you will see backlight bleed — pale patches, usually at the edges — and any lines running across the panel.

Then move the lid slowly through its whole range while the screen is on. Flickering that comes and goes as the lid moves is a display cable problem, and it is inside the hinge, which is one of the more awkward places to work.

The keyboard and trackpad

Open a text box and press every key, including the function row and the arrows. You are looking for keys that do nothing and keys that type twice. Both are common on a machine that has been used properly for a few years, and a keyboard is usually replaceable — but you should know before you pay, not after.

Run a finger over the keys and look at the shine. Heavy wear on WASD or on the number pad tells you what the machine was used for.

For the trackpad: move a pointer slowly across the whole surface, and click in each corner.

The body and the hinges

Open and close the lid a few times. It should feel firm the whole way. A hinge that has started to go will feel loose, or will lift the plastic around the screen when you open it — look for a gap or a crack at the bottom corners of the lid. Hinge damage tends to get worse quickly, and it eventually pulls the display cable apart.

Look underneath for screws that are missing or chewed, and at the edges for a case that no longer sits flush. Both mean the machine has been opened, which is not automatically bad, but it is worth asking about.

The battery

Do not trust the percentage on the screen. On Windows, open Command Prompt and run:

powercfg /batteryreport

That writes an HTML file — the command tells you where — with the battery's design capacity, its full charge capacity now, and usually a cycle count. The ratio of the second number to the first is the battery's real health. There is a whole article on this: what battery health and cycle count actually mean.

Then unplug the charger and leave the machine running while you do everything else on this list. A battery that drops from 100% to 60% in ten minutes has told you something the report might not.

The storage

Find out whether it is an SSD or a mechanical hard disk, and how big. This single fact affects how the machine feels more than anything else on the specification sheet. If it is a hard disk, budget for an SSD.

If you can, check the drive's SMART health — free tools will read it and tell you the reallocated sector count and the power-on hours. A drive with reallocated sectors is a drive on its way out. On an SSD, look at the percentage of life used.

Ports, camera, sound and wireless

Work through them one at a time, because this is where a quick look misses things:

• Every USB port, with something plugged in — not just one of them
• The HDMI or display output, on an actual screen if there is one available
• The headphone socket, and the speakers on their own
• The camera and the microphone, using any app that shows both
• Wi-Fi, by connecting to something, and Bluetooth, by pairing something
• The card reader, if it has one

Heat, noise and speed under load

Everything above tests the machine at rest. Now make it work: open fifteen browser tabs, or play a high-resolution video full screen, and leave it for ten minutes with your hand near the vent.

You are listening for a fan that screams from a standing start, and feeling for a base that becomes too hot to keep a hand on. Then watch what happens to the speed. A machine whose cooling has clogged with dust will run fast for four minutes and then slow dramatically — that is thermal throttling, and it is usually a cleaning and re-pasting job rather than a fault, but again: know first.

Signs of liquid

Look into the keyboard at an angle under a light for a faint tide mark, and at the ports for any green or white powdery deposit. Liquid damage is progressive: a machine that has had a spill can work perfectly for months and then fail for no visible reason.

What to ask the seller

• Why is it being sold?
• Has it ever been repaired, and what was done?
• Is the charger the original one, and does it come with it?
• Is the operating system properly licensed?

The part most people skip

Buy where you can see the machine and come back to it. A photograph cannot show you a loose hinge, an intermittent keyboard or a fan that only screams under load — and neither can a listing.

Every laptop tested before sale — and there is a physical shop in Udaipur where you can run through this whole list yourself, on the actual machine, before you decide. Bring a pen drive with a white image on it if you want to be thorough. Nobody will mind.