Malware is any software intentionally designed to cause damage to a computer, server, client, or computer network. A wide variety of malware types exist, including computer viruses, worms, Trojan horses, ransomware, spyware, adware, rogue software, wiper and scareware. 

Best approach is to think of protection as an onion. There are many different layers needed to prevent malware attacks at home and in your business.

Keep all your computers and software up to date

Malware encompasses all types of malicious software, including viruses, and cyber criminals use it for many reasons, such as:

Tricking a victim into providing personal data for identity theft

Stealing consumer credit card data or other financial data

Assuming control of multiple computers to launch denial-of-service attacks against other networks

Infecting computers and using them to mine bitcoin or other cryptocurrencies

The most common signs that your computer has been compromised by malware are:

Slow computer performance

Browser redirects, or when your web browser takes you to sites you did not intend to visit 

Infection warnings, frequently accompanied by solicitations to buy something to fix them

Problems shutting down or starting up your computer

Frequent pop-up ads

The more of these common symptoms you see, the higher the likelihood your computer has a malware infection. Browser redirects and large numbers of pop-up warnings claiming you have a virus are the strongest indicators that your computer has been compromised.