A reader asks:
If I have Windows Defender, do I need to buy anything else to protect my computer?
If your computer is running the Windows 8 operating system, Windows Defender will help protect you from viruses, spyware, and other malicious software. You don’t need to buy anything else.
If your computer is running Windows 7, Windows Vista, or Windows XP, Windows Defender removes spyware, but to protect yourself from viruses, you’ll need to download antivirus software. You can purchase it from a third party, or you can download Microsoft Security Essentials for free.
More ways to protect against viruses and other malware
Run newer software. Advanced security technologies in modern operating systems are specifically designed to make it more difficult, more complex, more expensive, and therefore, less appealing to cybercriminals to exploit vulnerabilities.
Regularly install updates for all your software. Update your antivirus and antispyware programs, browsers (like Windows Internet Explorer), operating systems (like Windows), and word processing and other programs. Learn how to turn on automatic updating.
Make sure your firewall is turned on. A firewall will also help protect against viruses and hackers. Find out if your version of Windows has a built-in firewall.
For more information, see How to remove and avoid computer viruses.