"I purchased KeyFinder software to get the product key from my wife's older Windows XP CD and didn't have the the product key code letters/numbers. That CD wasn't installed on our computers. The company does state that you can't retrieve the code from the CD, but only at the bottom FAQ's. It turns out that using their software, you can only get the product key from the Registry file in your computer.
They didn't write back after I asked specifically if I could get the code from the CD (which you can't). So it was a waste of my money.
Update: Support did write back after 4 days."