Thanks for that advice, but I was referring to uninstallation/reinstallation of StartAllback, not Windows. I think what has happened is that the StartAllback servers allowed installation on a new PC on my LAN, when it should have registered that installation had already been done on three PCs. As a consequence, regardless of my uninstalling StartAllback and its license on that new PC, when I fired up a PC where StartAllback had originally been installed, that was considered to be in excess of the three license limit. I can still register StartAllback on that new PC, but what I need is for that license to be valid again for the PC where it was originally installed.