The product key for Windows 10 is hardware based, embedded into the motherboard's BIOS, and is inaccessible except by the operating system. If your system is asking for a product key, you can try to manually activate it by entering slui 4 into the Windows Run box. This will open a window that will display a phone number and a string of characters unique to your computer. Call the number on the screen to attempt to reactivate Windows manually over the phone. If this does not work, your next steps might include contacting the system's manufacturer support for assistance, or in some instances, reinstalling Windows to see if that will help. If you recently purchased the affected PC from Micro Center, you might also check in-store with the Micro Center Knowledge Bar or Walk-In Support Office for further assistance.

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Where is my product key for Windows 10 retail versions.