registry: how to get the key from previous installed windows

[gohand]

I have a previous installed windows that cannot start up anymore, now i had to start it up from another hard drive, and back it off from this new drive, but since i've been moved from my old house my key original key was lost, which the previous windows is using, is anyone know if i can rechieve my old windows key even it's not on my own drive? thanks in advance.

 

[Trotter]

I use Belarc Advisor:
http://www.majorgeeks.com/download.php?det=1385

 

[EricB]

me. rock xp

http://www.majorgeeks.com/download4138.html

 

[gohand]

thanks but the problem is i'm not trying to find the key in the current installation, i'm looking for the key in my previous installation(which cannot be booted up, and is in another hard drive hooked into this same pc) is there any other ways around?