What is antivirus software?
Antivirus software is a computer program that detects, prevents, and takes action to disarm or remove malicious software programs, such as viruses and worms. You can help protect your computer against viruses by using antivirus software, such as Microsoft Security Essentials.
Note: In Windows 8, Windows Defender replaces Microsoft Security Essentials. Windows Defender runs in the background and notifies you when you need to take specific action. However, you can use it anytime to scan for malware if your computer isn’t working properly or you clicked a suspicious link online or in an email message.
Learn more about Windows Defender.
Computer viruses are software programs that are deliberately designed to interfere with computer operation; record, corrupt, or delete data; or spread themselves to other computers and throughout the Internet.
To help prevent the most current viruses, you must update your antivirus software regularly. You can set up most types of antivirus software to update automatically.
For on-demand protection, the Microsoft Safety Scanner allows you to visit a website and scan your computer for viruses and other malicious software for free.