- Yes, sysprep needs to be run from the original system. I do not believe you can generalize a random drive in a whole different PC.
- Sysprep is not for an old extensively customized install. It is for building a new OS and a few applications, generalizing it for deployment across a company.
As I see it, a "migration" is not in the cards here. The original Win 7 system does not work.
If it did, you could have (probably) upped it to Win 10, and then the potential to moving to different hardware is a little bit better. Still not a guarantee, though.
Create a vhd from that Win 7 drive, and use it within a VM tool like VirtualBox.
That is the only real way forward I see. ANd that, only short term. The Win 7 license will balk after 30 days. A VM is literally a "different PC" and a Win 7 wants to be licensed in that "different PC".
So you'll have a new system running WIn 10, and a guest VM of WIn 7 on that system.
You WILL need to install whatever applications you use on the WIn 10 system, and then possibly/maybe export whatever settings exist in that db software in the Win 7 VM.
Also, you can
try booting up the Win 7 in the new hardware. But I wouldn't do that with the only copy of that data, and I would expect a greater than 50/50 chance of complete fail.