Whether you just unboxed a new computer or picked up a used PC and monitor from a marketplace listing, the smartest time to find a problem is the day it arrives, not three weeks later when you're already used to it and the return window has quietly closed. Secondhand sales in particular often come with short, strict return conditions, so it pays to run through a complete checkup the moment you open the box. Every check below runs directly in your browser, with no software to install, and nothing you type, record, or capture is ever uploaded anywhere.
Before you start testing
- If this is a secondhand purchase, confirm the return or refund window and conditions before you buy, not after. Policies differ enough between marketplaces, retailers and individual sellers that no single number applies everywhere, so check the specific listing or store policy for your purchase.
- Take photos of the box, included accessories (power cable, manuals, authenticity stickers) and any visible scratches or dents before you do anything else. If a dispute comes up later, dated photos from day one are the most convincing evidence you can have.
The 12-step checkup order
- Check the basic specs — Open Check My PC Specs and compare the operating system, number of CPU threads, memory, graphics card, and monitor resolution/refresh rate against what you ordered. The browser can't report an exact CPU model name or disk capacity due to privacy limits built into browsers themselves, but it's more than enough to catch a spec that's clearly wrong or downgraded.
- Test the keyboard — Use the Keyboard Tester to press every single key and watch for keys that don't register or ones that fire twice within about 40ms (a sign of switch chattering). For a deeper read on interpreting the results, see the keyboard test guide.
- Test the mouse — The Mouse Click Test checks left/right/middle clicks, scroll wheel behavior, double-click chattering, and click speed (CPS). If it's wired, you can also check the polling rate in the same tool.
- Test the screen for dead pixels and bleed — Run the full-screen solid color test in Dead Pixel & Backlight Bleed Test to look for stuck pixels, dead pixels, light bleed around the edges, and uneven brightness. The monitor test guide walks through exactly what to look for at each color.
- Test the refresh rate — If you paid for a 144Hz, 165Hz or higher refresh-rate monitor, confirm it's actually running at that rate with the Monitor Refresh Rate Test. Many Windows installs default new monitors to 60Hz until you manually select the higher rate in Display settings, so a low reading here often just means a settings change is needed, not a hardware fault.
- Test the mic, camera and speakers — If this PC will be used for video calls or recording, run the Mic, Webcam & Speaker Test to confirm microphone input, webcam resolution/fps, and that both the left and right speaker channels work independently.
- Check internet speed and IP — Use Internet Speed Test to measure download, upload and latency, and What Is My IP Address? to confirm the network connection and router setup look correct.
- Check disk health — This matters most on a used PC, where SSD wear is the single biggest hidden risk. Follow the SSD and hard drive health guide to check drive health through Windows Settings and PowerShell.
- Check Windows activation — Follow the Windows activation check guide to confirm the license is genuinely active. If a used PC shows as not activated, raise it with the seller immediately before the return window closes.
- Check CPU temperature — If the machine runs hot even under light use, that can point to a cooling or thermal paste problem. The CPU temperature and normal ranges guide explains how to read Task Manager or a free monitoring tool and what counts as normal.
- Check Windows 11 upgrade eligibility — If the machine still runs Windows 10 or you're considering upgrading, the Windows 11 upgrade eligibility guide covers TPM 2.0, Secure Boot and supported CPU lists.
- Document everything — Save screenshots or photos of any problem you found during the steps above, and contact the seller or retailer while you're still inside the return or warranty window.
Extra checks for a used PC or monitor
Secondhand hardware can carry wear and repair history that a new unit simply doesn't have. Add these to your pass:
- Physical condition: look closely at laptop hinges, the area around ports, and screw heads for signs the case has been opened before.
- Battery health (laptops): Windows can generate a battery report showing full-charge capacity and charge cycle count, which tells you how worn the battery really is compared to when it was new.
- Software history: check for unfamiliar installed programs, and it's worth running a quick malware scan on anything bought secondhand before you start storing your own files on it.
- Activation and licensing: covered in step 9 above, but worth repeating — a business license resold to an individual buyer can cause problems down the line, so confirm the license type matches the sale.
Why this order matters
The order isn't arbitrary. Software-only checks (specs, keyboard, mouse, internet) come first because they take seconds and immediately tell you whether the machine is even the one you ordered. Screen tests come next because they benefit from being done early, before the panel has had any chance to develop new issues from heat cycling. The guide-linked checks (disk health, activation, CPU temperature, Windows 11 eligibility) come last because they take a few extra minutes each and are less likely to reveal a dealbreaker — but skipping them on a used PC is exactly how people end up stuck with a dying drive or an unlicensed copy of Windows weeks after the return window has already closed.
Printable checklist
Print this table or save a screenshot and check off each row as you go.
| # | Item | Tool | Done |
|---|---|---|---|
| 1 | Basic specs match the order | Check My PC Specs | ☐ |
| 2 | Every keyboard key registers | Keyboard Tester | ☐ |
| 3 | Mouse clicks, scroll, double-click check | Mouse Click Test | ☐ |
| 4 | Dead pixels and light bleed | Dead Pixel & Backlight Bleed Test | ☐ |
| 5 | Refresh rate matches the label | Monitor Refresh Rate Test | ☐ |
| 6 | Mic, webcam and speakers | Mic, Webcam & Speaker Test | ☐ |
| 7 | Internet speed, IP, network setup | Internet Speed Test / What Is My IP | ☐ |
| 8 | SSD / disk health | Disk health guide | ☐ |
| 9 | Windows activation status | Activation check guide | ☐ |
| 10 | CPU temperature (idle and under load) | CPU temperature guide | ☐ |
| 11 | Windows 11 upgrade eligibility | Windows 11 upgrade guide | ☐ |
| 12 | Physical condition, accessories, return policy | Manual check | ☐ |
Frequently asked questions
How many days do I have to check a used PC?
Return and refund windows vary a lot by marketplace, retailer, and seller, so check the return policy before you buy and plan to finish this entire checklist well inside that window. Dead pixels and keyboard or mouse chattering sometimes only show up after a few days of normal use, so it's worth testing again a day or two after the first check if you still have time left.
Do I need Windows to be activated to run these checks?
No. The keyboard, mouse, monitor, refresh rate, mic/camera, internet speed and IP checks all run in your browser and work regardless of activation status. That said, activation status is itself one of the things worth checking on a used PC, which is why it's a separate step on this list.
Does this order work for laptops too?
Yes, almost unchanged. The main difference is that a laptop also needs a battery health check, and you'll be testing the built-in keyboard and trackpad rather than external peripherals. The monitor and refresh rate tests work the same way on a laptop's built-in screen.