How to tell if your computer has been hacked, plus what to do if it happens to you

Not sure how to tell if your computer has been hacked? Cyber security experts explain the telltale signs

a laptop on a dining table
(Image credit: Chris Tubbs)

Ever wondered how to tell if your laptop has been hacked? It might not be the most prominent question in your mind, so how about another... How many smart devices do you have in your home? The answer is probably quite a lot, and almost certainly at least one - after all, you're reading this article on one right now. But how many of those devices are susceptible to hacking, and are they safe to use? 

We've been living in a technological age for quite some time, but ever since the pandemic our reliance on electronic devices has accelerated. As the internet plays a more vital role in our everyday lives, we're increasingly dependent on our computers and laptops as part of a smart home. But with increased dependence comes increased potential for hackers. 

A recent report from Which? revealed that a home kitted out with smart devices, including popular tech items such as smart thermostats and video doorbells, could be exposed to more than 12,000 hacking or scanning attacks in a single week. While most of our devices are equipped with internet security or antivirus software to fend off attackers, some weaker devices are more susceptible to hackers from across the world. 

But what is hacking, and how can it affect our devices? Put simply, hacking is the gaining of unauthorized access to any system or computer, and it can happen for a variety of reasons.

Noa and Nani Ludvig Office Desk Computer Table in Classic White and Natural Pine

(Image credit: Noa and Nani Ludvig Office Desk Computer Table in Classic White and Natural Pine)

Computers are often hacked for data theft, allowing criminals to gain access to the user's passwords or bank details. In other instances hackers will use ransomware to lock a device or limit its use until a ransom is paid, or a device with a camera can be hacked for surveillance. 

Computers can be an easy target for hackers, but in the PC vs laptop comparison, laptops are more at risk. As they're transported easily, we often use them to connect to public internet access, such as free airport Wi-Fi. These systems are often more insecure and therefore a simple way for hackers to monitor our devices. 

We've asked the experts the key signs to look out for and what steps to take if you suspect your laptop has been hacked. 

 What are the signs of a hacked computer? 

There's no single sign to look for when it comes to how to tell if your computer has been hacked. Sometimes, there's even no indication whatsoever. Yet, there are some telltale signs to look out for when using your laptop. This could be the sudden appearance of applications on your desktop that you haven't installed, or maybe your contacts receiving strange messages from you. 

There are giveaway signs to be wary of when you're using the internet, too. ‘Look for things like pop-ups in the corner of your screen or internet web pages not behaving as you would expect,’ says Darren Northfield, a cyber security professional at Aurora Tech Support

According to cybersecurity professional and author of Bullseye Breach: Anatomy of an Electronic Break-In Greg Scott, a slow computer could also be a sign of your device being hacked. 'One big sign to watch out for is your laptop behaving differently than earlier. Maybe it feels slower, maybe pop-ups show up, maybe your home page is different. Something will have happened to cause those changes.' 

 Can your computer be hacked without you knowing? 

As mentioned, the signs of a hacked laptop aren't always clear, and sometimes there are simply none at all. When signs do show, they're often well disguised. Hackers are great at replicating websites or software that look legitimate for malicious purposes, so when we open these dodgy webpages or applications, we don't realise the threat they pose. 

According to Greg, this means our mistakes often play a part in our computers being hacked. 'Open a malicious email attachment, visit an evil website, expose your unprotected device to the internet - all these things can lead to a successful compromise of your device.' 

What's the worst that could happen if your computer is hacked? 

The worst outcome for most hacking victims is the loss of money. These hackers are criminals and most of them use their skills to steal our money in some way. Some victims have lost their whole life savings after hackers have gained access to their personal information. 

But how does this happen? 'The most likely scenario is somebody will steal your passwords, bank, credit, and other account numbers - and then steal your identity,' explains Greg. 'Another possibility is ransomware where somebody scrambles all your files, including your 20,000 vacation pictures from last summer, and then offers a decryption key in return for a “small” payment.' 

It's hackers' ability to access our online banking that poses the biggest threat to our finances, however. 'Some hackers wait until you are logged in to online banking to move your money away to a separate account controlled by them,' adds Darren from Aurora Tech Support.  

What should you do if your computer has been hacked? 

If you suspect that your computer has been hacked, it's important to act fast and call a professional as soon as possible. The manufacturer is likely to have a team that can help you, or you can call another tech support company. 

It goes without saying, you should stop using the device and especially avoid accessing any personal accounts or inputting passwords. This applies to all your important information stored outside your laptop, too. 'Use another device to change all your passwords, credit cards, and account numbers, and consider freezing your bank accounts,' says Greg. 

While it's important to contact manufacturers and support services, be cautious of suspicious phone calls. As Darren explains, 'a phone call from someone claiming to be from your internet company or phone company who claim there’s an issue on your line is a well known scam tactic by hackers'. 

How to clean a laptop keyboard

(Image credit: Jourdan Wee / Pexels)

 Does shutting down your computer stop hackers? 

You might think the easiest way to deal with a suspecting hacking is to shut down your computer. While appropriate security software, such as anti-malware tools, might make this possible, in most cases it's unfortunately not that simple. 

'If hackers have made a connection but not yet managed to install software then yes, shutting down your computer will cut them off,' says Darren. 'However if a hacker has already managed to install remote access software, simply shutting down will not be enough.' 

Even if you do manage to stop a attack that's in progress, it's likely it will only resume when you turn your laptop back on. If you suspect your laptop has been hacked, shut it down and don't restart it until you can hand it over to a professional.  

If you're looking you're looking to buy a new laptop and want to know which is brand 

Color & Trends Editor

Lilith Hudson is the Color & Trends Editor at Livingetc. Writing news, features, and explainers for our digital platform, she's the go-to person for all the latest micro-trends, interior hacks, and color inspiration you need in your home. Lilith discovered a love for lifestyle journalism during her BA in English and Philosophy at the University of Nottingham where she spent more time writing for her student magazine than she did studying. After graduating, she decided to take things a step further and now holds an MA in Magazine Journalism from City, University of London, with previous experience at the Saturday Times Magazine, Evening Standard, DJ Mag, and The Simple Things Magazine. At weekends you'll find her renovating a tiny one-up, one-down annex next to her Dad's holiday cottage in the Derbyshire dales where she applies all the latest design ideas she's picked up through the week.