Christina is audience development editor. After graduating from the University of Nottingham reading philosophy and theology in 2013, Christina joined a tech startup specialising in mobile apps. She has a keen interest in the mobile platform and innovative tech.
Spyware is a type of software that secretly monitors and obtains information from PCs.
It can collect valuable information such as passwords, card details and other confidential information by discreetly recording keystrokes and web browsing history.
While most types of spyware are malicious, some uses are legitimate, for example, parents monitoring their children's internet use or an employer keeping tabs on employee devices.
Read next: Best vulnerability scanners.
If your PC is infected with spyware, it might be hard to spot. This kind of malware uses other programmes running on your device to conceal itself and make it difficult to detect and remove.
If you start to notice your PC is becoming sluggish and you're getting more than the average amount of ads and popup ads, you might be infected.
We list some of the best tools out there. If we are missing some you've used and loved, let us know.
Some of the products listed are general antivirus packages that include spyware removal, however there are some great standalone spyware removal tools included too.
Read next: Best online privacy tools.