United States   Change  |  All Microsoft Sites

Search Microsoft Security
Search Microsoft.com

Resources

Download free educational materials, learn security terms, watch videos, or see our latest research.

What is antivirus software?

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.

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.