You can use an installer on any number of machines it's the Windows Key that you can use a limited number of times. It seems a solution Microsoft came up with was to tie the Product Key to a Microsoft account. Then you can transfer the Key between different machines with less issues.
What I'd do is put the disk/usb in. Bring up the custom install menu. Completely format the HDD. Then proceed to install. Make sure the charger is plugged is so it doesn't shutdown this time.
