Unfortunately, this is the wrong forum for your question.
MSDN stands for Microsoft Developer Network.
It's intended for supporting developers who are writing software using Microsoft technologies.
Windows Forms is one such technology.
This is not a forum intended for supporting end consumer questions and it's not just about windows.
Good luck.
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I think you probably want the forum this thread is in:
http://answers.microsoft.com/en-us/windows/forum/windows_8-windows_install/invalid-product-key-windows-8-provided-by/54489102-53a6-4a5e-864d-5089b8ca34c5?auth=1
Note that changing the hardware since it was built can cause a similar problem. Maybe the same. I don't know, I'm a developer and don't do end consumer support.