As promised, Microsoft today released its Security Essentials beta, the free product for fighting viruses, spyware, rootkits, and Trojans that is replacing Redmond’s paid Windows Live OneCare subscription service. The beta is available in 32 and 64-bit flavors for the first 75,000 users, although Microsoft says this is a target number, and it is willing to increase it if necessary – just like it did with Windows 7 Beta.

Microsoft is pitching the software as a basic antimalware solution that consumes less memory and disk space than commercial security suites from the likes of Symantec and McAfee. Users can download MSE from Microsoft Connect by going to microsoft.com/security_essentials, logging in with their Windows Live ID, and taking a seven-question survey. If you are not put off by the extra steps, you’ll find download links for XP, Vista and Windows 7. Not surprisingly, the software won't work with pirated or non-validated versions of Windows.