Activation error and corrupted windows.old

Hello,
I recently did a clean install of windows 10 (over my free upgrade of windows 10 from 8.1). Previous windows 10 version was properly activated and I used it for 6 months.

In this process something went wrong and the installer created two windows.old ( naming windows.old and windows.old.000). Windows.old.000 seems to be corrupted and that version was not activated hence it has the generic key of 8hvx7. Because of this I am getting Key Activation Error 0xC004C003

I found out the original authentic key from windows.old using showkeyplus software.

I want to remove that corrupted windows.old.000 but want to keep windows.old and I would like windows to automatically recognize my authentic key.

Should I just enter my key or should I delete windows.old.000?

Please help. Thanks

Windows 10 never activates itself from Windows.old. You can try entering the Windows 8.1 key you recovered. A clean install after an activated upgrade is supposed to activate itself by retrieving the digital entitlement from Microsoft activation servers, not from Windows.old. You have the correct product key for Windows 10 Home that you are supposed to have for a digital entitlement activation.

Windows 10 never activates itself from Windows.old. You can try entering the Windows 8.1 key you recovered. A clean install after an activated upgrade is supposed to activate itself by retrieving the digital entitlement from Microsoft activation servers, not from Windows.old. You have the correct product key for Windows 10 Home that you are supposed to have for a digital entitlement activation.

Now I am getting new error.

By any chance, did Showkey show a product key stored in bios which would be listed as the OEM key?

By any chance, did Showkey show a product key stored in bios which would be listed as the OEM key?

Yes it does shows the OEM key and OEM Edition which is "win 8.1 RTM" which was pre installed on my laptop

I would try that key, then.

I would try that key, then.

It gives me this error when I enter that key

So let's try this to figure out what might be going wrong.

Run winver and post the result window here. Also, open an elevated ("run as administrator") command prompt and run:
slmgr /dlv

post that result here. Maybe we can then see where the disconnect is happening.

Everything looks good there. I'm afraid it looks like your only options are going to be to temporarily install Windows 8 and make sure it is activated correctly, then go back to Windows 10 and you should be able to use the same product key that activated Windows 8 to activate Windows 10 - or you can do the upgrade from 8 to 10 again - or you can capture the genuineticket.xml file in Windows 8 to activate Windows 10 with. Or purchase a product key for Windows 10.

I am not sure if deleting the Windows.old.000 would then allow you to revert back using Windows.old or not.

You can do a temporary install of Windows 8 on a separate hard drive or if you have room make a partition for it on your current hard drive. Personally, if it was me, I would back up what I want to save on a USB thumb drive or USB hard drive, wipe the installed hard drive and start over from scratch with a new install of Windows 8.