All genuine Windows XP CD or DVD come with a product key printed on it. You need to use the product key while installing Windows XP on a system. But in case you have forgotten or lost the product key no and have to reinstall a program or make a fresh installation of Windows XP or even have to repair Windows XP, you won’t be able to do it. All fresh installations along with the repair asks for Windows XP product key and you can’t proceed with the installation until and unless you provide the product key number.

Product key number can be easily found from the registry editor, but it’s pretty difficult to locate and use. Thank God, there are some applications, known as Windows XP key finder that you can use to find the product key automatically. All you have to do is simply install these product key finders and they will automatically find the product key of the installed Windows XP copy.

Here are some Windows XP product key finders that you can use to trace and find Windows XP serial no :

Magical Jelly Bean Keyfinder
Winkeyfinder
Keyfinder Thing
LicenseCrawler
WinGuggle
ProduKey
geProductKeys Finder
Product Key Finder
KeyFinder Pro
RockXP
Product Key Informer
MSKeyViewer Plus

Even if you have purchased a computer where your system came with a pre-installed copy of Windows XP, you can run these key finders to get the generic product key number that your system manufacturer used during installation.