You CANNOT use an OEM License (from the COA sticker) from one computer on another computer.
Replacing the motherboard on a computer outside the warranty conditions invalidates the license.
OEM Licenses are non-transferable.
You'll have to purchase a new license for Windows, or revert back to the original OS on the system you're currently using.
Noel Paton | Nil Carborundum Illegitemi |
CrashFixPC | The Three-toed Sloth