When you install Office 2007, you'll be prompted to type or paste in the 25-character Product Key that looks something like this:
Important: Although you aren't required to enter your Product Key at installation, we recommend you do so because it helps to verify that your software is legitimate. You can run your Office 2007 programs up to 25 times before you're required to enter a Product Key. After this grace period, if you haven't entered a valid Product Key, the software goes into Reduced Functionality mode and many features are unavailable.
You can find the product key in one of the following locations:
Sticker on the CD case or other packaging.
Certificate of Authenticity.
Confirmation email message received from an online purchase.
Important: Don't lose your Product Key. Keep the packaging, or write the number down and keep it in a safe place. If you lose your Product Key and have a valid proof of purchase, contact Microsoft support for help.
If it's hard to read the product key on your packaging, use this guide to help you tell the numbers and letters apart:
If your Office product key doesn’t work, or has stopped working, you should contact the seller and request a refund. If you bought a product key separate from the software, it’s very possible the product key was stolen or otherwise fraudulently obtained, and subsequently blocked for use. Unfortunately, there are many dishonest sellers who offer stolen, abused, or otherwise unauthorized Microsoft product keys for sale. Sometimes these product keys are printed on counterfeit labels or cards with a download link to Microsoft software, and sometimes they’re distributed with software media that is unauthorized for resale, such as promotional media, original equipment manufacturer reinstallation media, or other Microsoft program-specific media.