Microsoft Code of Authencity – Windows XP OEM, Windows Vista OEM and Windows 7 OEM For systems shipped with Windows XP, Windows Vista and Windows 7 a Code of Authenticity (COA) with a 25 digit product key was shipped affixed to the system. There was a change in print quality of the COA when Windows Vista was released which made the COA prone to fading. As a consequence for most Windows 7 systems the COA was Placed in the Battery Compartments of Laptops to Reduce the Problem of Fading. What is Original Equipment Manufacturer System Locked Preinstallation Activation? Install Palm Software From Sd Card. Examples of Microsoft’s Major Partner Original Equipment Manufacturer (OEMs) are: • Alienware/Dell • Lenovo/IBM • HP/Compaq • ASUS • Acer • Samsung • Sony • Toshiba • MSI • Fujitsu Microsoft Major Partner OEMs preinstalled Windows 7 on millions of machines. In order to save production time these Major OEM licenses utilised a BIOS based activation mechanism and as a consequence the key on the COA is typically not used for Windows Installation.