Windows Defender is a free program that helps protect your computer against pop-ups, slow performance, and security threats caused by spyware and other unwanted software. It features Real-Time Protection, a monitoring system that recommends actions against spyware when it's detected and minimizes interruptions and helps you stay productive.

Improvements in Windows Defender
Enhanced performance through a new scanning engine.

Streamlined, simplified user interface and alerts.
Improved control over programs on your computer using enhanced Software Explorer.
Multiple language support with globalization and localization features.
Protection technologies for all users, whether or not they have administrator rights on the computer.
Support for assistive technology for individuals who have physical or cognitive difficulties, impairments, and disabilities.
Support for Microsoft Windows XP Professional x64 Edition.
Automatic cleaning according to your settings during regularly scheduled scans.