Almost two years after it purchased GIANT Company Software for its best-of-breed antispyware solution, Microsoft has shipped its own nonbeta version of the product. Now called Windows Defender, the free add-on protects Windows XP users against spyware and other malicious software. A version of Defender will be included in Windows Vista as well.

Microsoft purchased GIANT Company Software in December 2004, shortly after shipping XP Service Pack 2 (SP2), which included pervasive security features. At the time, Microsoft said its version of the GIANT tools, then called Microsoft Windows AntiSpyware, would complement the features in XP SP2.

Over time, Microsoft renamed Windows AntiSpyware to Windows Defender, added the application to Vista, and built connections between Defender and related products such as Microsoft Internet Explorer (IE) 7.0, which was released last week, and Windows Live OneCare, Microsoft's subscription-based PC-health solution.

Windows Defender is available in 32-bit and 64-bit versions and supports Windows Server 2003 SP1, XP SP2, and Windows XP Professional x64 Edition. You can download a free version of Windows Defender at

http://www.microsoft.com/defender/