1. if the new PC is completely different e.g. different mobo, proc, etc. I would not clone the OS. Fresh installation is thousand times better.
2. If you have oem license, reactivation on new PC will not work as easy as that even if you have tied it to your microsoft account. It depends on in which country you live, you might have either to contact ms customer service to reactivate the windows or to buy new copy.
3. regardless of the activation status, you can install windows on your new pc and activate it later e.g. buy a new license later.
4. if your windows copy is not oem, you can simply tie it to your ms account...voila...you can simply install the the new pc with your windows copy and simply login using your ms account...it is as...