What are the 10 worst things you can do to a Windows PC?

worst things to do to a Windows PC
Avoid blackout: ten things to avoid doing to your PC

PCs – they’re not as easy to break as they used to be, but they’re not exactly bulletproof, either. Careless clicks or over-enthusiastic tinkering can easily leave you looking at a black screen that refuses to boot.

Here, by way of warning, we’re going to list the 10 worst things you can do to a Windows PC. To be clear, we’re talking about things you might conceivably do accidentally. We’re not talking about deliberate acts of sabotage. Driving over your laptop with a Land Rover or spraying the screen with superglue will definitely do more damage than anything we’ve got on our list…

1. Turn the PC off during a Windows Update

Windows is getting better at recovering from an interrupted update, but if there’s one thing on this list that we’d avoid like Charles Manson at a BBQ, it’s cutting the power during a Windows Update.

This normally happens accidentally: you don’t notice the subtle “Shut Down and Update” label instead of merely “Shut Down” when you close down the PC, and you pull the plug just as an update gets underway. Laptop owners get a lifeline here, as the machine simply falls back on battery power to complete the update.

If this does happen to you, don’t panic. The next time you start the PC, Windows will attempt to roll back the update. Fingers crossed, it should go fine. But you have got a decent backup, haven’t you?

2. Manually uninstall programs

Granted, I’ve not heard of anyone doing this in a while, but I’ve definitely come across friends’/relatives’ PCs where they thought they could uninstall software by simply deleting the program’s folder from the Program Files folder on the main hard disk.

This is a massive no-no. This will delete the program’s files, but leave behind a trail of digital debris that will leave the PC believing the program is still installed. Then when you come to try and uninstall it the proper way, Windows will stumble because it can’t find the original files.

If you want to uninstall a piece of software, search settings for Add or Remove Programs, or find that function from within the Control Panel on older versions of Windows. This will get rid of everything associated with the program.

3. Edit the registry if you don’t know what you’re doing

There are all manner of smart-arse articles online that tell you how to solve a Windows problem by editing the Windows registry. What they often don’t tell you is, if you screw it up, you can write off your Windows installation.

The registry is a database of settings for Windows itself and any software you’ve installed. If you accidentally wipe the registry or keys held within it, Windows may not boot properly or be able to find the software you’ve got installed. You’ll suddenly become intimately familiar with dense error codes.

My advice is not to touch the registry unless you’re 100% confident you know what you’re doing. Even if you are as smugly self-assured as Piers Morgan, make sure you back up the registry before making any edits, just in case. If you need me to tell you how to do that, you shouldn’t be tinkering with the registry in the first place.

4. Join the Windows Insider programme – and then leave your PC for a few months

Been there. Done that. The Windows Insider programme allows you to play with new releases of Windows before they’re released to the general public. I used an old laptop to tinker with a new build of Windows, preferring not to risk my day-to-day machine with unfinished code.

When I’d written my feature about the new Windows features, I put the laptop back in the cupboard for a few months. The next time I needed it, I was trapped in a Catch-22. Windows refused to install the latest update and the trial version of the operating system had timed out, meaning the computer would shut down after 30 minutes. In the end, I had to wipe clean and start from scratch.

So, if you’re planning on becoming an Insider, make sure you switch the PC on every once in a while.

5. Blindly click ‘Yes’ on installers

Software developers – particularly developers of ‘free’ software – are cunning swines. They will sneak little extras into installers, so that when you think you’re merely clicking ‘Yes’ to the boring licence agreement, what you’re actually agreeing to is to install five other pieces of crap that help them pay their bills.

Pretty soon, your PC is festooned with adware that runs automatically when the PC boots and plagues you with pop-up ads, browser plugins and all sorts of other undesirable klutz.

6. Running without security software

One of the best decisions Microsoft ever made was to build antivirus software into Windows, thus giving the ‘I’m not paying for security software’ brigade no excuse.

However, there are still some foolhardy morons out there who will switch that off, believing that they’re not at risk because they don’t open dodgy attachments and that security software slows their PC.

Yes, there might be a tiny performance hit from running anti-malware – but no one, not even “experts”, are immune from attack. Malware can be injected into legitimate sites by ads, for example, and you’ll never know it’s on your system. Malware rarely makes itself known anymore.

Antivirus software doesn’t guarantee safety. Stuff might still slip through. But you’ve got a much better chance of not having your PC encrypted with ransomware, for example, if you have it switched on.

7. Use your laptop in bed

Laptop in bed

This is the first case of phyical harm in our top ten – and one that I’m constantly yelling at my kids for. Blame Jennifer Aniston romcoms where she’s constantly doing this…

Using your laptop in bed, with the duvet between you and the computer, is akin to lighting a match and chucking it on the keyboard.

The duvet not only insulates the warm base of the device, it blocks the air vents on either side. Hence a warming laptop has no means of cooling itself.

If you’re lucky, the laptop will just shut itself down when its sensors detect it’s overheated. If you’re not, a component will burn out and you’ve got yourself an expensive new doorstop.

8. Running disks at close to capacity

It’s not your fault. The Saturday gimp in PC World told you 128GB is plenty for a laptop. It’s not. Now you’re fighting a running battle to clear space every time you want to install a new piece of software, as your disk is 95% full.

As a rule of thumb, never let a disk get more than 90% full. Everything will slow down due to the way that Windows works (it likes spare disk space to “borrow” as extra memory or RAM). What’s more, the fuller a hard disk is, the harder it has to work to find free space in the first place, slowing things down even further.

If you can’t afford to replace a full PC, plug in an external drive and store files on that to free up space on your main hard disk.

9. Let your kids use an admin account

Give your child an admin account and ten minutes of unsupervised access to the internet, and it’s entirely possible they will have downloaded every piece of malware the web has to offer and provoked a nuclear war with North Korea.

Don’t give the little toerags the opportunity to wreak havoc. At the very least, lock them down on a regular user account instead of your main admin account so that they can’t download seven shades of malware without your password. WHICH YOU SHOULD NEVER GIVE THEM. EVER.

To do this in Windows 10, search for “users”, click on Add, Edit or Remove Other Users, and select Add A Family Member. Select Add A Child and Windows will run you through a series of steps that allow you to place restrictions on the sprog’s accounts, including what apps they can use and even what times they’re allowed to use the PC.

10. Ignore strange noises or beeps

Hear a noise like a cat dragging its claws down a dustbin? That’s probably a sign your hard disk is on its way out.

Strange beeps when you first switch on the PC? That’s the POST (power on self-test) telling you something has gone awry. There’s a list of what all those POST beeps mean here.

Much like a car, if you can hear a strange noise, don’t ignore it. Replacing or repairing a component inside your PC before it completely fails is normally less painful, and potentially less costly if it takes other components with it. Case in point: faulty fans causing your processor to overheat.

NOW READ THIS: What does the Windows key do?

About the author

Barry Collins

Barry has scribbled about tech for almost 20 years for The Sunday Times, PC Pro, WebUser, Which? and many others. He was once Deputy Editor of Mail Online and remains in therapy to this day. Email Barry at

Add Comment

Click here to post a comment

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.