Buying a used or refurbished laptop: 5 tests that catch costly problems.

Used and refurbished computers can be great value, but a few problems are expensive enough to erase the savings. Run these tests before you hand over money. Each takes a few minutes.

1. Keyboard and touchpad

Open a blank document and test every letter, number, arrow, function, Shift, Ctrl, Alt, and Enter key. Then confirm the touchpad tracks, clicks, and scrolls smoothly. Sticky, repeated, or unresponsive inputs can point to wear or liquid damage, and a keyboard or top-case replacement can quickly erase the savings.

2. Screen

Display solid white, black, red, green, and blue images in full screen. Look closely for dots that never change color, dark patches, bright pressure marks, flickering, or uneven backlighting. These are easy to miss on a busy desktop and may require an expensive screen replacement.

3. Battery health

Do not rely only on the percentage shown. On a Windows laptop, open Command Prompt and run powercfg /batteryreport, then compare Full Charge Capacity with Design Capacity in the saved report. A much lower full-charge figure means shorter unplugged use, and a battery replacement may be needed soon.

4. Ports and charger

Plug a known-working device into each USB port, connect headphones to the audio jack, confirm the charger fits securely, and test video output when possible. A dead or loose port can be expensive to repair, especially on a laptop.

5. BIOS or UEFI lock

Ask to see the BIOS or UEFI settings open without requesting an unknown administrator or supervisor password. That low-level lock can block drive changes, booting from a repair USB, or reinstalling Windows, and it may be difficult or impossible to remove without the previous owner.

Then ask about the warranty

Ask what happens if something fails in the first few weeks. For reference, here is the 30-day limited warranty on items bought from David.