Upgraded to W10, downgraded to W7 unconventionally, won't activate

pugseason said:

Are you kidding me... man, I didn't know it wasn't legitimate when I bought it. Windows licensing is complicated as hell. I don't know how any of this works. I thought it was legitimate but he just wasn't gonna give me the sticker or something... well wait, how does it work now though? if it's not legitimate then how come Windows activated it on my original W7 installation and it worked with my W10 upgrade? Can anyone explain to me like I'm 5?

I do not wish to go into detail regarding the illegal activation employed on your machine, I'd just mention that an OEM marker has been injected into the bios to spoof a Windows 7 OEM PC... you can check in the registry under HKEY_LOCAL_MACHINE\HARDWARE\ACPI\RSDT which OEM they copied.
MS has 'till now not found a way to counter this and thus Windows 10 cannot differentiate a genuine from an illegal version.

The marker on it's own is useless without a matching certificate and can be left there if you want... or a bios update from the motherboard's manufacturers website will remove it.

System builder keys, are OEM but are not the same as those employed by the large companies (which activate against the above combo offline )- i.e they activate online like retail - they carry a special EULA for personal use, however.

NavyLCDR said:

Could it be that the builder of this custom computer just recycled an OEM motherboard from a pre-manufactured computer and didn't actually mess with the bios?

Possibly, but they still need to find the correct certificate to activate it, which makes me think the install was a bit more deliberate.

You can still do a standard install of Windows 7, on a PC with an OEM marker, and not use the marker. You just use a Retail disk and type in your key manually. If it's a legitimate key it will activate online. Showkey will still show the marker as being there, it doesn't mean it was actually in use though. I'm just saying. It does sound like something isn't on the up and up, but hard to say 100% one way or the other. Now that being said, if it was an OEM-SLP install, and the key retrieved was the OEM-SLP key, that would explain why the new install won't activate. OEM-SLP keys are blocked from online activation. Like Superfly says, without the custom OEM install media and the matching certificate file, activation will fail. To reinstall Windows 7 with stock install media, you need the key from the COA sticker. If there is no sticker, that's another indication of a fake install. Just Google the last 5 digits of that key and you should know pretty quickly if its an OEM-SLP key.

It wouldn't happen to be > Home Premium = RHPQ2-RMFJH-74XYM-BH4JX-XM76F would it. If it is that key is almost certainly blacklisted by Microsoft.