An upgrade works on any Elements version. It can also be version 2! I don't know if a previous version has to be registered with Adobe or not, but an installation on a PC works even if no version was installed before. It needs an Adobe account. One product key can be used on 2 PCs. The Organizer part still works on the other PC, but the Editor can only be registered twice. When changing PCs, the editor must be deactivated via the programme function in the editor (Help -> Logout) and then re-registered on the new PC.