if the activation failed you will not be able to make the setting changes.
the activation will fail if reuse the wrong type of key or the key was already in use.
generally you can migrate a retail key from one system to another but you might have to call microsoft and tell them you are replacing a motherboard and want to transfer the licence to an new machine. Last time I did that I had to read off the old key, the made sure the old key was not a pirate key, then they just read a new key for me to use. They had me type in the new key while they waited and made sure I typed it in ok and was activated.
took about 5 minutes for the full phone call.
if you have a OEM key you can not transfer it to a new machine.
if activation fails, I think the system will check once a week for activation, if it passes, it will not check activation for 90 days