The reasons for the difficulty (why you can't copy software over...) is the registry, shared dlls and more.
Windows (as of 1995) is designed to hamper such software movement.
So that's it, uninstall and reinstall as needed.
Bob
PS. Yes there is Aloha Bob PC Relocator but you are fighting a losing battle here. It doesn't always work.
I've a 40gb HD with 2 equal partitions. Win2000 on part. C, Win Vista Ultimate on part. D. My question is how can I get all the software previously installed on the computer's C partition to be recognised and run by the Vista OS on the D partition? Do I need to re-install all the software or is there a way to get Vista to run it from C. Thanks!

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