Windows SteadyState Installation Overview

Windows SteadyState works with genuine versions of Microsoft Windows XP with SP2 or SP3 installed, Windows Vista, and Windows Vista SP1. SteadyState works on 32-bit versions for the following operating systems: Windows XP Professional, Home Edition, and Tablet PC Edition are supported, as well as Windows Vista Business, Enterprise, Ultimate, Home Basic, Home Premium, and Starter. The hardware requirements are the same as for Windows XP and Windows Vista, so any computer that runs these operating systems well should also be able to run Windows SteadyState. See the Windows SteadyState Handbook for more detailed hardware specifications.

Uninstall any previous version of Windows SteadyState or the Microsoft Shared Computer Toolkit for Windows XP, an earlier version of Windows SteadyState.
See how to uninstall.

It is very important to defragment your hard disk before using Windows Disk Protection. There are a number of other steps that are also highly recommended, such as clearing out caches, histories, cookies, temporary files, and anything else that users shouldn't see. The idea is to clean out and update everything on the PC to get it in the exact condition you want it to return to every time it restarts.
Read the optimization checklist.