Its a problem for a lot of people. They have a program they MUST have and they lost the installer for it and the program is to old to get a copy of.
Sooner or later, like when the hard drive dies the user will have no choice but to move on. But until that is forced you wont get a user to do it lol
When a program is installed it all depends on the program, but files, regkeys and all sorts get modified and added to the system. thats why you cant just move it to a new system. Thats one reason why people love portable versions of programs, no installer needed as it has every thing it needs in the folder.
But almost all older programs are not that way and will have a ton of things added to the system for it to work. MS office is a good example.
So right now xenon is in a tight spot. A broken OS that is limping along but all those programs that cant get reinstalled. Only thing he can do before reinstalling is try everything possible to fix what is broken. But the bad news is the core of Windows is broken and one thing after another is failing.
Instead of trying to find a way to avoid a reinstall I say focus on finding a way to get your programs moved and workable! Would be easier and better at this point.
Shane