As far as I know, it only works one way. You can install a program from an installer, but you can’t create an installer from an installed program.
Of course, this applies to
installed programs. In contrast,
portable programs, which don’t require installation,
can be copied and carried around even on a USB memory stick, as their name implies. One more reason to choose portable apps instead of installed ones. And there are more reasons, but they would take us off topic.
Now, getting back on topic, you don’t say what program it is. It’s also strange that a “valuable” program is no longer available. Even if it’s not, almost always there are many alternative ones that will do the same job, some of them possibly freeware.
Anyway, in theory, there is a very round-about and highly impractical way of getting the program from your laptop on your desktop. First create a backup of all your files that are on your desktop system partition. Then create an image of your entire laptop system partition and install that on your desktop, replacing its own system partition content. Then uninstall all apps you don’t want and re-install the ones you originally had on your desktop. Finally, transfer your backed-up files back on your desktop.
Far better, forget the whole above idea of mine!
