I know there are quite a few Windows 10 activation issues, but I'm not sure if it pertains to me or not because the "official" wiki article describing the issue below doesn't really mention my method of installation. I came from the Insider preview builds and got Windows 10 for free, I never upgraded from Windows 8.1 or any other previous version of Windows. On the machine that I had installed Windows 10 on, it upgraded to the final build as normal and said it was activated. I then downloaded Windows 10 using the 64bit tool on the Insider page, chose to put it on a flash drive and proceeded to perform a clean install. During install it prompted me for a product key, which I'd assume is normal, the only product key I was given was the one I was given during the preview builds, which apparently did not check out and I couldn't use it for the install so I ended up skipping the activation during install. So now Windows 10 is installed, but not activated, and is not giving me any of the errors mentioned in the wiki article below, so I have no idea what to expect exactly. The error I'm receiving on the activation page is "Error code: 0xC004C003" and under that it says that the product key entered as been blocked ... but I didn't enter any product key, which is just confusing me even more. Has anyone else came from the preview builds as I did and experiencing the same issue? I have no problem waiting, but not having a clear idea if this clean installation is actually going to activate is a bit annoying and seemingly wasting my time. Just incase you might be wondering, I am logged into my Microsoft account associated with the Insider program, and is the same account I've used since I started using the preview builds.
http://answers.microsoft.com/en-us/insider/wiki/insider_wintp-insider_install/how-to-activate-and-resolve-common-product-key/33f31475-93b3-4d1c-812f-4b21fbd807a7