Microsoft Security Essentials
Microsoft Security Essentials (MSE) is a free antivirus software created by Microsoft that provides protection against computer viruses, rootkits, spywares, and trojans for Windows XP. MSE x86 (32-bit) replaces Windows Live OneCare, a commercial subscription-based antivirus service and the free Windows Defender, which only protected users from adware and spyware. It is geared for consumer use, unlike Microsoft's upcoming enterprise-oriented product Microsoft Forefront.