CD Lost Key

The Keyfinder got me. Is there any software out there that can reveal the product key of a CD that is not installed?

I bought Windows XP Home Editiion. I installed it properly and everything worked.

I had accidentally removed the sticker thathad the key with the wrapping on the manual and trashed it. A few days later when I neededthat key during some patch installation, not Microsoft or the vendor could help. Three days later ihad to go purchase another copy.

I still have this copy sitting in my wallet. But I will like to install it on another home PC.

Any help out there?