Microsoft has gone to great lengths to end software piracy. Nevertheless, piracy still occurs every day. Oftentimes victims of piracy are unaware that they have purchased counterfeit software until it is too late. Most counterfeit software is sold online, especially on auction sites and on sites claiming to offer software at a great discount.
Go to the Microsoft Genuine Software website in your Web browser. A link is provided in the References section below.
Click "Validate" at the top of the screen.
Click "Validate Office" on the left side of the screen.
Install the Firefox plug-in if using the Mozilla Firefox Web browser, or the Active X control if using Internet Explorer. Once these add-ons are installed, the validation process will automatically begin, you'll type in your product key and your results will be displayed.
If your product key is not valid, you will be presented with options on how to obtain a valid key. In some cases you may qualify for a free product key or a product key at a discounted price. Visit Microsoft's website for more information.