The latest versions of Windows* come with Windows Defender to help protect your PC from viruses and other kinds of malware.
If you’re looking to protect a PC with an older version of Windows*, Microsoft Security Essentials helps guard against viruses, spyware, and malicious software of all kinds. You can't put a price on protection—so we didn't. Designed to be easy to use, Microsoft Security Essentials is a free** program that runs in the background, so you don’t have to be bothered by updates or interruptions.
Stay Up To Date
Install the latest service packs or other free** updates to help make Windows more reliable and secure.
Get More Tools
This is the place to find useful extras, utilities, and add-ons to get the most out of your PC.