|What I am suggesting is a reasonable course of action given your criteria.|
You need to install NT so you can access the formerly mirrored drive. Which hopefully you can then access to run the password software.
The problem isn't just the mirror but the fact the disk is dynamic. This is why you need NT at the same service pack level you had before to try to access the disk.
You are pretty well out of recovery options here especially since there appears to be no backup.
Ideally the newly install NT on the former shadow drive will see the primary formerly mirrored drive successfully so you have access. If that fails you would see if the option in disk manager of "import foreign disk" is available. After that you are at the end of the road.
Something to consider, though this should have been done with the shadow drive, is using utilities to convert from dynamic to basic again. Usually this is a destructive [wipes out all data] but I have been seeing references online to software that can do a nondestructive conversion.
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