My recommendation to you is to start from scratch as sjesse suggested and moving forward snapshot your golden image at each major steps. That way if something goes wrong you can always revert to a previous snapshot rather than start over from scratch.
I do not have tool in front of me at the moment, but there is a section or tab that shows what registry changes were made for each item in the template. Then you can track down the registries and change them back. It is very tedious.