2) was released on February 13, 2006. It featured the program's new name and a redesigned user interface. The core engine was rewritten in C++, unlike the original GIANT-developed AntiSpyware, which was written in Visual Basic. This improved the application's performance. Also, since Beta 2, the program works as a Windows service, unlike earlier releases, which enables the application to protect the system even when a user is not logged on. Beta 2 also requires Windows Genuine Advantage (WGA) validation. However, Windows Defender (Beta 2) did not contain some of the tools found in Microsoft AntiSpyware (Beta 1). Microsoft removed the System Inoculation, Secure Shredder and System Explorer tools found in MSAS (Beta 1) as well as the Tracks Eraser tool, which allowed users to easily delete many different types of temporary files related to Internet Explorer 6, including HTTP cookies, web cache, and Windows Media Player playback history. German and Japanese versions of Windows Defender (Beta 2) were later released by Microsoft. First release On October 23, 2006, Microsoft released the final version of Windows Defender. It supports Windows XP and Windows Server 2003; however, unlike the betas, it doesn't run on Windows 2000. Some of the key differences from the beta version are improved detection, redesigned user interface and delivery of definition updates via Automatic Updates. Windows Defender had additional functionality in Windows Vista which was removed in subsequent versions of Windows: Security agents Security agents which monitor the computer for malicious activities: Auto Start – Monitors lists of programs that are allowed to automatically run when the user starts the computer System Configuration (settings) – Monitors security-related settings in Windows Internet Explorer Add-ons – Monitors programs that automatically run when the user starts Internet Explorer Internet Explorer Configurations (settings) – Monitors browser security settings Internet Explorer Downloads – Monitors files and programs that are designed to work with Internet Explorer Services and Drivers – Monitors services and drivers as they interact with Windows and programs Application Execution – Monitors when programs start and any operations they perform while running Application Registration – Monitors tools and files in the operating system where programs can register to run at any time Windows Add-ons – Monitors add-on programs for Windows Software Explorer The Advanced Tools section allows users to discover potential vulnerabilities with a series of Software Explorers. They provide views of startup programs, currently running software, network connected applications,