
Not surprisingly, Microsoft's software won't work with pirated or nonvalidated versions. There is one caveat, though: You need to have a validated copy of Windows. Installation of the 32-bit Vista version on my machine took less than five minutes and was about as simple as an installation can be. Both are light downloads: The 32-bit Vista download weighs in at 4.8MB, the 64-bit Vista version at 3.8MB and the XP version (there's only a 32-bit version) comes in at 7.6MB.

Security Essentials comes in versions for XP and Vista (the Vista version will also work with Windows 7).
