This is used to reinstall the operating system in the event of a system crash. To access it, you will need to boot into when you start your computer by pressing a function key. This can be either F1, F2, F9, F10, F11, F12 or even DEL or Tab key..A Certificate of Authenticity COA or Product ID will never be required to setup, configure or use the Windows operating system that was included with your computer, or to use the recovery media provided with or created from your computer. These computers utilize both a Universal ID specific to .A Certificate of Authenticity COA is a label that is used to identify genuine Microsoft Windows software. The COA included with Acer products is not used to reinstall the operating system. For desktops, the COA is located on the right side of the system near the bottom..Microsoft Windows Server Certificate of Authenticity COA labels are used to help customers identify genuine Microsoft Windows Server software. Every OEM Windows Server Operating System OS must have a COA label. HPE Windows Server 2016 Standard ROK COA..