There will be a time when you may have to find product key of your installed Windows of Microsoft Office software. This could happen if you have to reinstall your operating system, and you don’t have the original installation CD, or the sticker on your desktop PC is unreadable. You may be able to find an OEM installation CD on the Internet or in a computer store, but you need the right key to complete the installation.

What you need is a program that can access the registry, find this key and show it to you.

Complete keyfinder is one of the tools that can do this. It’s a free program which lets you access this information, and if you register it, it can even show you the product key of any external drive attached to the computer. Thanks to Computer Aid for publishing a post about this wonderful program.

Another tool that is quite popular is Magical Jellybean KeyFinder, but there are many more that let you do the same thing, and they are all free! See for yourself – here is the list:

• Winkeyfinder
• Keyfinder Thing
• License Crawler
• ProduKey
• Product Key Finder
• Keyfinder Pro
• WinGuggle
• RockXP
• Product Key Finder (by OTT Solutions)
• MSKeyViewer Plus
• geProductKey Finder
• Product Key Informer

All of these programs let you retrieve Windows (7/Vista/XP) and most versions of Microsoft Office and even some other programs. For more information on these programs including detailed reviews, please visit the About.com Web site.