The most effective way to avoid computer viruses is to combine four habits: keep your operating system and software updated, use antivirus software, avoid clicking suspicious links or downloading files from untrusted sources, and back up your important files regularly.

Viruses spread when you run infected files or visit compromised websites. Most people catch them by opening email attachments from unknown senders, downloading software from unofficial sites, or clicking links in messages that look like they came from banks or social media platforms but didn't. A few straightforward practices stop the vast majority of infections before they start.

The good news is that you do not need to be technically skilled to protect yourself. The steps are the same whether you use Windows, macOS, or Linux, and they take minutes to set up once and then run mostly on their own.

Key Takeaways

  • Enable automatic updates for Windows, macOS, or Linux so security patches install without you having to remember to do it manually.
  • Install antivirus software such as Windows Defender (built into Windows), Bitdefender, Norton, or Kaspersky, and run a full scan at least once a month.
  • Never open email attachments from people you do not know, and do not click links in messages claiming to be from your bank or payment service unless you initiated contact first.
  • Back up your files to an external hard drive or cloud storage so that if a virus does encrypt or delete your data, you can restore it without paying a ransom.

Turn on automatic updates for your operating system

Every month, Microsoft, Apple, and Linux distributors release patches that fix security holes in their operating systems. Hackers find these holes and write code to exploit them within days or weeks. If you do not install the patch, your computer remains vulnerable.

On Windows 10 or 11, go to Settings > Update & Security > Windows Update and turn on "Automatic updates". Your computer will read and install patches in the background, usually overnight. On macOS, go to System Settings > General > Software Update and check "Automatically keep my Mac up to date". On Linux, the process depends on your distribution, but most have a software update tool in the system menu that you can set to automatic.

Restart your computer when prompted after an update. The patch does not take effect until you do. If you see a notification that updates are waiting, restart as soon as you can save your work.

Install and run antivirus software

Antivirus software scans files on your computer and compares them against a database of known viruses. It blocks suspicious files before they run and alerts you if something looks dangerous. Windows comes with Windows Defender built in at no cost, and it is effective for most users. If you want additional protection or prefer a different brand, Bitdefender, Norton, Kaspersky, and Avast are all widely used.

After you install antivirus software, run a full system scan at least once a month. This takes 30 minutes to an hour depending on how many files you have. Schedule it for a time when you are not using your computer. Most antivirus programs also run a quick scan automatically every few days in the background.

Do not install more than one antivirus program at the same time. Two antivirus programs conflict with each other and slow your computer down. If you switch from one to another, uninstall the old one completely before installing the new one.

Recognize and avoid phishing emails and malicious links

Phishing is when someone sends you an email or message that looks like it came from your bank, PayPal, Amazon, or another service you trust, but actually came from a criminal. The message usually says your account has a problem and asks you to click a link to "verify" your password or payment information. The link takes you to a fake website that looks identical to the real one, and when you enter your details, the criminal captures them.

Real banks and payment services never ask you to verify your password by clicking a link in an email. If you get a message claiming to be from your bank, do not click the link. Instead, open your web browser, type the official website address yourself, and log in to check your account. If there is a real problem, you will see it there.

Be suspicious of attachments from people you do not know, even if the email looks professional. Criminals often send files disguised as invoices, resumes, or delivery notices. If you were not expecting an attachment, ask the sender to confirm they sent it before you open it. Hover your mouse over a link (without clicking) to see the actual web address it points to—if it does not match the company name in the email, it is a phishing attempt.

Use strong, unique passwords and enable two-factor authentication

A strong password is at least 12 characters long and includes uppercase letters, lowercase letters, numbers, and symbols. Avoid passwords based on your name, birthday, or common words. If a website is hacked and your password is stolen, a strong password is harder for criminals to crack.

Use a different password for each important account—your email, bank, and social media especially. If one site is breached and your password is exposed, criminals will try that same password on other sites. A password manager like Bitwarden, 1Password, or Dashlane stores all your passwords securely so you only have to remember one master password.

Enable two-factor authentication (also called 2FA) on accounts that offer it. Two-factor authentication means that even if someone steals your password, they cannot log in without a second piece of information—usually a code sent to your phone or generated by an app like Google Authenticator. Most banks, email providers, and social media platforms offer this feature in their security settings.

read software only from official sources

Malware often hides inside software downloaded from unofficial websites. If you need a program, read it from the publisher's official website or from your operating system's app store. On Windows, use the Microsoft Store. On macOS, use the App Store. On Linux, use your distribution's package manager.

If you read software from a third-party site, check the URL carefully to make sure it is the real publisher. Criminals create fake read sites with names very similar to the real ones. For example, a fake site might be "vlc-media-player-read.com" when the real VLC site is "videolan.org". When in doubt, search the company name plus "official read" to find the real site.

Be cautious of free versions of paid software, especially antivirus programs. Some fake antivirus programs are actually malware themselves—they claim your computer is infected and demand payment to remove the threat, but there is no real threat. Stick to antivirus software from established companies like Windows Defender, Bitdefender, Norton, or Kaspersky.

Back up your files regularly

Ransomware is a type of virus that encrypts your files and demands payment to unlock them. If you have a recent backup of your files, you can restore them without paying. Backups also protect you from accidental deletion, hardware failure, and theft.

Back up your files at least once a month to an external hard drive or cloud storage service. External hard drives are inexpensive—a 1 or 2 terabyte drive costs $50 to $100 and plugs into your computer via USB. Cloud storage services like Google Drive, OneDrive, Dropbox, or iCloud offer free plans with limited storage (usually 5 to 15 gigabytes) and paid plans for more.

For maximum protection, use both: keep an external drive at home for fast backups, and use cloud storage for files you need to access from multiple devices. Disconnect the external drive from your computer when you are not backing up—if your computer gets infected, the virus cannot spread to the backup.

Frequently Asked Questions

What should I do if I think my computer has a virus?

Disconnect from the internet when ready, then run a full antivirus scan. If the scan finds and removes a virus, restart your computer and run the scan again to make sure it is gone. If the scan finds nothing but your computer is still behaving strangely, restart in Safe Mode (hold Shift while restarting on Windows, or hold Command-S on macOS) and run the scan again. Safe Mode loads only essential programs, so viruses are easier to detect and remove.

Is it safe to use public Wi-Fi if I have antivirus software?

Antivirus software protects against viruses, but public Wi-Fi has a different risk: other people on the network can see unencrypted data you send. Avoid logging into your bank or email on public Wi-Fi. If you must, use a VPN (virtual private network) like ExpressVPN, NordVPN, or Proton VPN, which encrypts all your traffic so others cannot see it. Many VPNs charge a monthly fee, but some offer free versions with limited data.

Do I need antivirus software if I only use my computer for browsing and email?

Yes. Viruses spread through email attachments and compromised websites, so even light computer use puts you at risk. Windows Defender is free and runs automatically, so there is no reason not to use it. Run a full scan once a month to catch anything that slipped through.

Can I get a virus from visiting a website?

Yes, if the website is compromised or designed to spread malware. Your antivirus software and browser should block most malicious sites automatically. If a website asks you to read something or install a plugin to view content, close the page—legitimate websites do not require this. Keep your web browser updated, just like your operating system, because browsers are common targets for hackers.

What is the difference between a virus, malware, and ransomware?

A virus is a program that copies itself and spreads to other files. Malware is a broad term for any malicious software, including viruses, spyware, and adware. Ransomware is a specific type of malware that encrypts your files and demands payment to unlock them. Antivirus software protects against all three because they all behave suspiciously and are detected the same way.