To fully use your Microsoft Office product, you need to activate it. If you fail to activate after installing the product, Office will go into Reduced Functionality Mode. In Reduced Functionality Mode, you will not be able to save modifications to documents, or create a new document, and additional functionality may be reduced. No existing Office files will be harmed while the product is in Reduced Functionality Mode.
Also, through the Microsoft Office Activation Wizard, you may update or change your personal customer information held at Microsoft at any time either over the Internet or by telephone.