To find out if your Microsoft products are genuine, compare the anti-piracy features on your media and packaging to the features described below. (These features may vary by product edition and by purchase method).

To view previous versions of a selected anti-piracy feature, click View Previous Versions link below the anti-piracy feature image (where applicable).

For Windows software that comes pre-installed by a large manufacturer (also known as an Original Equipment Manufacturer or OEM) on a computer, the COA should be affixed to the body of the computer. The COA includes the 25-character product key, which may be required if a reinstallation is needed.

To confirm that you have a genuine Microsoft Windows operating system, look for the Certificate of Authenticity (COA) affixed to the body of your computer. COAs cannot be purchased separately. Each pre-installed Windows COA features the Microsoft product name printed near the top of the label and a 25-character product key. If your COA does not match this one, you may have a previous version.