Windows Defender is delivered free of charge from Microsoft and is designed to offer protection against pop-ups, slow performance and security threats via the Real-Time Protection monitoring system. With Windows Defender, Microsoft provides support for Windows XP and Windows Server 2003, both 32-bit and 64-bit editions.

Microsoft has introduced a number of enhancements to Windows Defender as the software exited the beta stage. Windows Defender features a new scanning engine that boosts performance, a streamlined, simplified user interface, globalization and localization features delivering multiple language support.

Other enhancements include:
- Improved control over programs on your computer using enhanced Software Explorer.
- 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.

The final version of Windows Defender is Build 1.1.1592.0 and users have the possibility to upgrade from the Beta 2 version, but not from Beta 1 (Microsoft Anti-Spyware Beta).

Windows Defender has been tested by Softpedia as being 100% Clean and is available for download here.