I have 4 keys in total: OEM Windows 7 Home Premium (SLIC Cert) OEM Windows 7 Home Premium (Sticker) OEM Windows 8 Pro (Embedded in BIOS) Retail Windows

I have 4 keys in total: OEM Windows 7 Home Premium (SLIC Cert) OEM Windows 7 Home Premium (Sticker) OEM Windows 8 Pro (Embedded in BIOS) Retail Windows 8 Pro None of them worked with a clean install, you have to manually upgrade your version of Windows, let the setup finish, and then you can do a clean install without introducing a key. Some people have already confirmed that Windows takes a fingerprint of your hardware and saves it into their activation servers. Honestly, I am concerned about the Retail Win8 key in case my motherboard breaks, but hopefully that won't happen in the next 5 years.