Computer repair top tips

If your computer develops a fault, here are some easy tips to try yourself before you fork out for a professional computer repair or a new model.

None of our suggested solutions risk further damage to your computer if you follow the steps carefully.

We've focused on repair tips for Windows PCs rather than Macs, as Windows PCs tend to be prone to more glitches – though some of the tips will also work for Macs.

Definitely need to replace a faulty laptop? See our expert pick of the best laptops.

If your computer starts up

Does your computer start up normally but then have a problem once it's started? For example, such as the screen freezing or it running very slowly? There are a number of tricks you can try.

1. Restart your computer

This has become a cliché but it solves many desktop and laptop problems. It's quick and easy so is always worth trying first. 

If your computer screen has frozen you can usually force a shut down by holding down the power button until the computer turns off, then start up again.

If it won't turn off, you can force a complete shut down: 

• Desktop PC Turn off the power at the mains
• Laptop Remove and replace the battery. If your laptop doesn't have a removeable battery, simply hold down the power button for at least 10 seconds to ensure it properly switches off. 

2. Back up your files

Even small problems, such as your computer running slowly, could be symptomatic of a bigger issue. To avoid losing important files and photos if the problem escalates, back up all your files to an external hard drive or to online cloud storage. 

Find out more about how to choose the best cloud storage.

3. Run computer security checks

If things aren't working as smoothly as they should or you're frequently experiencing problems, run a security scan. Some particularly malicious malware or viruses can stop your computer from starting, but more commonly they will just make your system sluggish. A security scan will put your mind at rest and will let you rule out malicious attacks at an early stage.

Protect your PC. We reveal the best antivirus that topped our tough tests.

4. Remove recently installed programs

If your computer has problems just after you've installed a device or a software program, uninstall the last piece of software you put on your system. 

To do this safely and fully, click the Start button, type Control and select the Control Panel. Next, select Add or remove programs. 

Once you've uninstalled the program, check for improvement. If everything's working OK again, you can try reinstalling.

5. Check for duplicate programs

Problems can arise if you have two versions of the same program running (for example, if you've reinstalled a piece of software to get the latest version, rather than using the program's update option). You can check if you have multiple versions of the same program running using the Windows Control Panel, which lists all the programs you've downloaded to your computer. 

• Windows 10, type Control Panel into your Windows search bar, select the Control Panel app. Next, select Programs and Features.
• Windows 11 click the on-screen Start button and select All apps

If you spot duplicates, uninstall both versions, and then try reinstalling (if you're installing from a disc, you may also need to check online for updates).

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6. Don't use more than one antivirus program

It's vital to protect your computer with appropriate security software. But running two antivirus programs on your computer isn't wise as they will interfere with each other. It's OK to have Windows Security enabled alongside a third-party antivirus program, however. 

If you have two different antivirus programs installed on your computer, make sure only one of them is active. Find out which security software we recommend in our pick of the best antivirus software.

7. Check for and install Windows updates

This is a straightforward way to ensure you're up to date, and it should improve the performance and reliability of your computer. You can set your computer up to check for and install Windows updates automatically. If you haven't already been running updates regularly then it may take some time to download all updates, but it's worth it.

Click Start, type Update and then select Check for updates.

8. Carry out a system restore

This is a powerful and effective tool that will fix many PC problems by reverting your computer system to the last state in which it was working well. Go to Start > All Programs > Accessories > System tools > System restore or just enter system restore in the Windows search box and press Enter.

Once you're in the main window, if you have an available restore point the date will be highlighted in bold. Click that date and simply follow the step-by-step wizard that will take you through the process and will even restart the computer for you. If it has restored successfully you will get confirmation.

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If your computer won't start up

Even if your computer won't start properly – or at all – you may still be able to fix the problem yourself.

1. Check your connections

If you've got a desktop computer, you may be having problems because one of the cables inside the machine has become loose, particularly if you've moved your computer around recently. Open up the desktop casing (not the computer monitor) – you'll need a small screwdriver. Check that all the cables are firmly pushed into their appropriate sockets.

Laptop loose connections are less likely, but if you've recently installed new memory it's worth making sure that you've firmly connected it.

2. Check your laptop battery

If you're running your laptop off its battery, try plugging it into the mains power – if it works fine off the mains, it's probably time for a new battery.

3. Start up in Safe Mode

Try starting up in Safe Mode. To do this, as soon as you switch on, repeatedly press the F8 key. You will be presented with an on-screen menu. Select Safe Mode – this should allow you to start up your desktop and in most cases will allow you to investigate further, including running a security scan.

Get expert help from Which?

If none of the computer repair solutions above work, it could mean some of your computer hardware is damaged – for example, your hard drive or motherboard. You can get one-to-one technology support from Which? in the following ways.

• Which? Tech subscribers can use our online booking tool to book a Tech Support appointment with our friendly team. It's relatively easy to install a new hard drive in a desktop, but it's much trickier with most laptops and many require a qualified engineer
• Not yet a subscriber? You can sign up to Which? Tech Support to get instant access to friendly one-to-one tech and computing advice from Which?
• Alternatively, use Which? Trusted Trader to find a local computer repairer you can trust.

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