One type of computer security problem can fall under the banner of viruses, but another set of security problems falls under the banner of "Malicious Software" (malware).
Malware can be spyware, ransomware and other malicious software.
Malwarebytes mainly looks for various types of malware.
Note MSE also looks for malware but it never hurts to have more than one anti-malware product.
You can get malwarebytes free from here (see below0.
Note during the install, near the end, you are asked if you want to try the chargable (PRO) product for 30 days. Just remove the tick from this option and you get the free product.
http://www.malwarebytes.org/