How to test a used laptop before buying it

A used laptop can look fine and still have a bad screen, unreliable keys, a weak battery or a slow drive. Test it before you pay, while you can still ask the seller questions or walk away.

Test Everything runs browser-based checks one by one and gives you a report. Bring the laptop’s charger, and ask the seller before running tests or changing settings.

Test the laptop before paying

1. Open Test Everything in the laptop’s browser and follow the prompts. Let the tests finish, and note anything that does not work as expected.
2. Check the screen and keys. Look closely for bright or dark spots, flicker, uneven colors and damage. Use the Display Test for screen checks and the Keyboard Test to see whether keys register.
3. Try the built-in camera, microphone and speakers if you will use them. The browser asks for permission before a camera or microphone test. If the seller does not want to allow access, skip those checks rather than changing settings without permission.
4. Check the battery while the laptop is unplugged, if the seller agrees and there is enough charge. Open Battery Meter if it is available, then plug in the charger and check whether the charging state changes.
5. Review the report and basic specifications before deciding. System Info shows details such as the processor, graphics, screen and battery. The Storage Test measures drive speed, but it does not check the drive’s full health.

Also inspect the laptop itself. Check that the lid opens smoothly, hinges are firm, the case has no swelling or gaps, and the charger cable and plug look undamaged. Try the ports with a device you brought, such as a USB mouse, if the seller permits it.

What the results mean

The screen has spots, flicker or uneven colors

A spot that stays in the same place across different colors may be a dead or stuck pixel. Flicker, lines or large areas with the wrong color can point to a display, cable or graphics problem. Run the Display Test again and check whether the issue remains. A minor pixel defect is still a defect, so decide whether the price and return terms make it acceptable.

A key does not register

Test the key more than once and check whether it feels sticky, loose or different from nearby keys. A single failed key may need a keyboard repair. Do not treat the Fn key, Windows key, Print Screen or laptop brightness and volume shortcuts as ordinary browser keys. The operating system often intercepts them before the browser can detect them.

The battery level drops quickly or charging does not start

Battery Meter shows the charge level, charging state, estimated time left and drain rate when the browser reports a battery. It does not measure the battery’s original capacity or prove how long the laptop will last in everyday use. If the charging state does not change, check that the charger is firmly connected and ask to try a known working compatible charger.

The laptop feels slow or the drive test is disappointing

Browser-based performance scores are useful clues, not a universal pass or fail. Results depend on the processor, background activity, temperature and power mode. Storage Test measures speed for large files and small writes; it does not report every possible drive fault or confirm the drive’s remaining lifespan. Ask what storage and memory the laptop is supposed to have, then compare that with its specifications.

A camera, microphone or speaker test does not work

First check whether permission was allowed and whether the correct device is selected. For a camera or microphone, a blocked browser permission can look like a hardware failure. Try again only after the seller agrees to allow access.

If a test fails

1. Repeat the check once. Close any other app using the camera or microphone, reconnect the charger, or reload the test. A temporary app or connection issue can affect a result.
2. Check browser permission. If a camera or microphone test was blocked, use the site controls beside the browser address bar to allow access, then retry. Do this only with the seller’s permission.
3. Check system privacy access. On Windows 11, open Settings › Privacy & security › Camera or Settings › Privacy & security › Microphone. On macOS, open System Settings › Privacy & Security › Camera or System Settings › Privacy & Security › Microphone. Make sure the browser has access, if the seller agrees to change the setting.
4. Reconnect the charger or accessory. Make sure plugs are fully seated and try another port. Do not force a plug that does not fit or wiggle a damaged connector to make it work.
5. Ask the seller to explain the problem. Ask whether it has been repaired, whether the fault is covered by a warranty, and whether you can test it again after a restart. A promise that a fault is easy to fix is not the same as a working laptop.

When a fault is a reason to walk away

One failed check does not always mean the whole laptop is unusable, but it should affect the price and your decision. A screen with lines, a loose charging port, repeated shutdowns, a swollen battery or several dead keys can mean an expensive repair. If the seller will not let you test basic features, cannot explain a serious fault, or pressures you to pay before you can inspect it, consider another laptop.

Battery Meter appears only when the browser reports a battery, and System Info gives only a rounded hint about RAM size, not an exact measurement. These browser checks can help uncover visible problems, but they cannot certify a used laptop or replace a repair inspection.