The fix for re-activation using the sys prep and wpa files will only work if there were no hardware changes. Any added or removed hardware will cause the fix to not work....

Your serch for the reg keys is futile in itself for the same reason as the system auto check requires matching to some ten different hardware profiles and comparing with what is known in the system. plus also known owner profiles...if any one doesn't match it triggers a new activation request. It is extremely difficult to find the indentity keys of a piece of hardware until it is installed and drivers are activated. and then you would need to swap the ID of the different hardware so as to match that what is known to the system...

If no hardware changes then just using the system prep fix would or should suffice and the rest would be moot.