From the developer: "WinPatch compares an old file system in one Windows 98/NT/2000/XP folder to a new file system in folder and creates a self-extracting patch file that can be distributed and used by others to update their set of files to the new version. You create self-contained, compressed patches for files already on the end-user's machine. You can use it to update only registered users of your software. WinPatch (and the WinPatch Wizard) is fast, easy to use, and powerful."