Windows Fundamentals for Legacy PCs

Windows Fundamentals for Legacy PCs ("WinFLP") is a thin client operating system from Microsoft, based on Windows XP Embedded and is optimized for older, less powerful hardware. It was released on July 8, 2006 and is not marketed as a full-fledged general purpose operating system, although it is functionally able to perform most of the tasks generally associated with one. It includes only certain functionality for local workloads such as security, management, document viewing related tasks and the .NET Framework. It is designed to work as a client–server solution with RDP clients or other third party clients such as Citrix ICA.
History.
Windows Fundamentals for Legacy PCs was originally announced with the code name "Eiger" on 12 May 2005. ("Mönch" was announced as a potential follow-up project at about the same time.) The name "Windows Fundamentals for Legacy PCs" appeared in a press release in September 2005, when it was introduced as "formerly code-named “Eiger”" and described as "an exclusive benefit to SA [Microsoft Software Assurance] customers".
A Gartner evaluation from April 2006 stated that:
The RTM version of Windows Fundamentals for Legacy PCs was released on July 8, 2006. The release was announced to the press on July 12, 2006.
In May 2011, Microsoft announced Windows Thin PC as the successor product.
Technical specifications.
Microsoft positions Windows Fundamentals for Legacy PCs as an operating system that provides basic computing services on older hardware, while still providing core management features of more recent Windows releases, such as Windows Firewall, Group Policy, Automatic Updates, and other management services. However, it is not considered to be a general-purpose operating system by Microsoft.
Windows Fundamentals for Legacy PCs is a Windows XP Embedded derivative and, as such, is optimized for legacy PCs. It requires significantly fewer system resources than the fully featured Windows XP. It also features basic networking, extended peripheral support, DirectX, and the ability to launch the remote desktop clients from compact discs. In addition to local applications, it offers support for those hosted on a remote server using Remote Desktop. It can be installed on a local hard drive, or configured to run on a diskless workstation.
Hardware requirements.
Despite being optimized for older PCs, hardware requirements for Windows Fundamentals for Legacy PCs are similar to Windows XP, although it is faster running on slower clock speeds than Windows XP.
Limitations.
Windows Fundamentals for Legacy PCs has a smaller feature set than Windows XP. For example, WinFLP does not include Paint, Outlook Express and Windows games such as Solitaire. Another limitation is the absence of the "Compatibility" tab in the "Properties..." dialog box for executable files.
Internet Explorer 8 (and 7) can be installed, but a hotfix is required for auto-complete to work in these newer versions of the browser.
Availability.
Windows Fundamentals for Legacy PCs was exclusively available to Microsoft Software Assurance customers, as it is designed to be an inexpensive upgrade option for corporations that have a number of Windows 9x computers, but lack the hardware necessary to support the latest Windows. It is not available through retail or OEM channels. 
On October 7, 2008, Service Pack 3 for Windows Embedded for Point of Service and Windows Fundamentals for Legacy PCs was made available.
On April 18, 2013, Service Pack 3 for Windows Fundamentals for Legacy PCs was made available for download again after previously having been removed from the Microsoft site.
The Microsoft marketing pages for Windows Fundamentals now redirect to those of Windows Thin PC, suggesting that Windows Fundamentals is no longer available for any customers.
Windows Fundamentals for Legacy PCs has the same lifecycle policy as Windows XP; as such, its support lifespan ended on 8 April 2014.