There are viruses that one can get from the internet or email attachments that can harm one's computer.
These are taken care of with a virus scanner.
There is another form of malicious software called spyware.
This problem needs a spyware scanner.
Some virus protection programs come with some basic protection, but it's best to use a separate spyware tool on your machine to remove these malicious files.
Why spyware is bad on your system? This type of software needs to be removed from your system because it can cause problems.
It will slow down your machine.
It can cause application errors.
It can hijack your internet browser and take you to pages that you don't want to go to.
It can log your usage on your computer and let others know about it.
It can even steal your login and password information.
That's why you need protection.
There are a wide variety of quality spyware tools most of which are free.
These will need to be updated regularly and will scan your system removing the latest problems that come up as new threats are out weekly.
Some spyware tools are malicious files in disguise.
Never attempt to download ones that you find in popups on your machine.
Be sure to get a tools that have positive reviews letting you know that it's a real scanner tool and not a scam or malicious file.
One thing that will never be able to protect you is if you download files from sites and run them on your machine.
Be careful about what you execute on your machine as many times these protection tools can't protect you from the programs you choose to run manually.
Do what you can today to make sure that you have proper protection from these types of programs and files.