Finding registration on hard drive

I have had a upgrade to the laptop which included wiping the hard drive. I can not find a copy of the registration key, it was purchased from a local supplier. I backed up the hard drive before the upgrade so assume the key is there somewhere. Can you advise how I can get the registration key back from the backed up hard drive?

Thanks

I just formatted my had and reinstalled, then I copied the entire BS2 folder back in and all is well

You will need your recipes, profiles... anyway
Good luck
Rick