Windows Live Essentials are part of what Microsoft is calling Windows Live Wave 4, the next revision of its "Live" line of software and services. Windows Live Essentials includes the photo organizing and editing tool Photo Gallery, and the video creation and editing tool Movie Maker.
Considering that they're free, both are very solid, useful programs, and well worth the download. The versions being worked on for Windows Live Wave 4 will focus on ways to connect to social networks, share photos and videos, and synchronize photos and videos among PCs, phones, and other devices, says Microsoft Corporate Vice President of the Windows Live Experience Chris Jones in a blog post.
On that same post, Jones responded to comments and confirmed that Windows Live Essentials won't run on XP, although Web-based versions of Windows Live services such as Hotmail and SkyDrive will still run on XP:
Windows XP is nearly 10 years old and simply doesn't provide the same level of platform support for graphics, and we recognized early in our work on Wave 4 that we could do much more in our software on a modern graphics platform. As a result our new version of Essentials will require the new graphics platform and controls that are only available on Windows 7 or Windows Vista and therefore will only run on these platforms.As for IE 9, it won't run on XP because IE 9 uses hardware acceleration via Direct2D and DirectWrite. Neither API is available on XP.
Expect more and more moves like this in the future. Just like Microsoft is doing its best to kill all remnants of Internet Explorer 6, it will do its best to kill XP as well.