SteadyState grew out of the U.S. Libraries Program from the Bill & Melinda Gates Foundation. The U.S. Libraries Program provided more than 60,000 PCs to 11,000 libraries during 2001 to 2003. Those "Gates PCs," as they were known, came with lockdown software called the Public Access Security Tool (PAST). When the Gates Foundation dropped support of PAST in 2004, Microsoft picked up with the Shared Computer Toolkit in 2005, which begat SteadyState in 2007.
SteadyState 2.5, the last version, was released two years ago. Microsoft never added Windows 7 to SteadyState's repertoire, nor did SteadyState support any 64-bit version of Windows. And now SteadyState is officially an orphan.
If you use SteadyState, it'll keep working after the end of the year -- Microsoft just won't support you any more. Even the support forum is scheduled to disappear next June.