Audio files and projects can usually be moved around between computers without issue.
Setup files/installers can be moved from one computer to another, but will need to be run on the new computer in order to install their software there.
Pre-installed programs and applications generally can not be moved. Those would need to be reinstalled.
Re-reading your first post, are you asking "Can I plug the old drive into the new computer, keep it plugged in, and access my data on it directly".
The answer to that is yes, but I wouldn't.
This old disc is the system disc from some other computer. If you want that computer kept it working condition, you'd want to take backups of the things you need and then put that old drive back.
If you don't care about the working condition of the old machine then that's fine, but I still wouldn't want to permanently keep its hard drive in a new computer.
As Dave (ecc83) discovered in your old thread you can run into issues there where the computer tries to boot from the wrong drive etc.
Not exactly a big deal but better to avoid.
My advice is to plug in your old drive, copy what you need from it, then put it back where it belongs.
If you want a second drive in the long term for data management or backup purposes, that's a good idea.
I'd buy a new one for that purpose, though. Preferably external so it's only connected when needed.
For the windows savvy amongst you, is there no automated migration tool?
Even if it only covered a user account; Settings, preferences, files within mydocuments/mypictures etc. Is that not a thing?