Microsoft Security Essentials (codenamed Morro) is a free antivirus software created by Microsoft that provides protection against viruses, spyware, rootkits, and trojans for Windows XP, Vista, and 7. Microsoft has always recommended that its users use real-time antimalware protection, but the release by the end of this year will mark the company's first free solution.

I myself Have activated my Windows XP Today ( 26-7-2009) in this way.
Please Follow the steps properly to validate successfully.
I Have Tested it on XP Sp2 and Xp SP3 ...
Enjoy!!

*The included "Silent Softwares Installation.exe" file will silently extract the actual installer and creates a shortcut to it on the desktop.
*It is highly recommended that you only use this installer on a freshly installed Windows where you have not installed anything extra yet. Similar existing softwares will get installed over.
*I am not responsible for any lost or damages. Try this installer within a virtual machine first!
*Windows Vista & 7: UAC will needs to be turned off for this installer to work correctly.
*If "msvcr71.dll" is missing from your system the nice looking blue skin of the installer will not load properly, but installation will work. Download the dll it for free and put it in the "Windows\System32" folder,This is an installer I created which includes 59 softwares that are mostly free or open source that can be selected individually to be installed silently (an automatic installation process without user's interaction needed). Most of the included softwares are freewares so you can download them elsewhere, this installer just help make installation faster in freshly installed Windows machine. A few softwares included are not free softwares: WMP11 which requires a genuine validated Windows, XP's 3D Pinball (this works with Vista and 7) and several bios needed for the game emulators. Otherwise there are no retails or sharewares included.

Latest Release hacking protection of Windows Genuine Advantage. Install and download any updates from Microsoft. If the load from the Microsoft Download Center Web site or the Microsoft Windows Update, you may be prompted to conduct the verification process Windows Genuine Advantage (WGA). If you choose the package loading, marked with WGA on the web site, Download Center, you may be prompted to install the control ActiveX. This update is required to access the download related to Windows. Version number 2 with the installer in the form of exe file.

How to Download Center Microsoft, and at the Windows Update Web site control ActiveX, known as Windows Genuine Advantage Validation Tool, checks to establish the authenticity of copies of Windows. Subject to the authenticity of copies of Windows loading can be continued. If the copy of Windows fails the authentication, the following message on the causes of breakdown in checking Windows.

100% working on Windows Update, Microsoft Download Center and Microsoft Update.

Office Genuine Advantage (OGA) is a similar tool as Windows Genuine Advantage (WGA) from Microsoft that checks and validates via an online validation process to verify that the copy of Microsoft Office System productivity suite or their individual applications installed on your system is genuine, licensed and legal.

This App Enables you to Activate and Validate All Windows OS they are as follows:-
Windows Vista
Windows XP Black Edition
Windows XP MEdia Center
Windows Xp Pro
Crystle Xp
Longhrn
Windows XP SP 2
Windows XP SP 3

Windows Defender (formerly Windows AntiSpyware) 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. Now with 2 free support incidents for Windows XP and Windows Server 2003.
Windows Defender detects and removes known spyware from your computer, which helps make your Internet browsing safer. This helps reduce negative effects caused by spyware including slow PC performance, annoying pop-up ads, unwanted changes to Internet settings, and unauthorized use of your private information. Continuous protection improves Internet browsing safety by guarding over 50 ways spyware can enter your PC.
The worldwide SpyNet community plays a key role in determining which suspicious programs are classified as spyware. Microsoft researchers quickly develop methods to counteract these threats, which are automatically downloaded to your PC, so you stay up-to-date. The software uses automatic definition updates provided by Microsoft analysts to help detect and remove new threats as the threats are identified.

Windows Defender features :
• New option to display Windows Defender system tray icon even when there are no pending actions needed.
• Enhanced performance through a new scanning engine.
• Streamlined, simplified user interface and alerts.
• Improved control over programs on your computer with enhanced Software Explorer.
• Multiple language support with globalization and localization features.
• Protection features 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.