I fitted a new hard drive, loaded the windows 8 professional (that was working fine on the old hard drive) but I now get the error message saying I cant upgrade with this version. I do have the disk with windows 7 that was originally on my laptop. Everything is working fine but keep getting the message to register windows, The help center says I should install windows 7 first then upgrade to win 8, but how do i do that as I now have win 9 installed. should I format the hard drive and start again?

To install an upgrade version of Windows 8, you must already have Windows 7, Windows Vista, or Windows XP installed on your PC.
If you formatted the drive before the upgrade version of Windows 8 was installed, you won't be able to use your upgrade product key to activate Windows 8. To activate Windows 8, you'll need to install your previous version of Windows, and then reinstall Windows 8. For help with the activation process, contact support.