In Most cases the software needs to be installed from the original media as daswilhelm points out. There are, however, some programs that can simply be run from within their sub directory. I have genealogy, collector and telecom applications that work just fine as they were designed this way. Windows 7 has two program directories: Program Files is for 64 bit applications and Program Files (x86) is for the older 32 bit applications. I placed my three programs in subdirectories within Program Files (x86) and simply created a desktop shortcut to them and they work just fine. Again this all depends upon how the program was designed so you may want to test this if you do not have the original media... BTW for Eudora you should be able to download this from their website.