In this context, I'd save the data on a separate drive.
After that, I'd try the procedure that?s' described in the following MSKB article:
Q307545 - "How to Recover from a Corrupted Registry that Prevents Windows XP from Starting"
If after Part One you're able to boot, then use that utility to extract the key. Later, it's up to you to try the subsequent steps or install fresh windows XP.
Probable only the original XP author of that part might know how to find the key. The third party utility can read it using undocumented wmi calls in a working Windows XP.
Trying to unweave, unwind, unravel
And piece together the past and the future,
T. S. Eliot
I hava a system that has had the product key sticker stolen off the box by a former employee.
It wasn't noticed by the owner until now. It has a non booting hard drive. No safe mode either. However I can see the contents of the drive when plugging into my system as a extra drive.
If there a way to get the key from the registry of that drive.
Programs like keyfinder, only look at the current loaded OS and don't let you specify a different registry to look through.