Ok I'm marking this as solved because I got what I needed to done, but if someone else has the same problem they are going to need some tricky stuff to get around it. Thanks for your help.
The Registry Editor just throws a bunch of errors because I'm not allowed to open the config file or open the SAM hive without an admin account, but that's fine. I think I can do it from here using some tricks that I'm not going to say here. Why can I even open the Registry Editor?
So I have the password to the hidden admin account, but no other accounts with admin privileges and I don't know how to log in with this password. I also have an older liveboot Ubuntu minipen that can access anything you feel like should you need.
Would any of you be so kind as to tell me a way...