Re: reFormating a Drive to use in new build
I don't think it'll matter if it boots or not. Just disconnect your other drives, pop your disk or usb stick in and install from there, you'll get an option to format the drive during your install
Edit : If your installing Windows 7 on a new board and cpu, make sure the new hardware is compatible with Windows 7 first. Much newer hardware is only compatible with Windows 10 today.
You can use your Windows 7 key to activate your Windows 10 install as long as they are the same versions ie: Home to Home or Pro to Pro
Windows 10 .... It wants to be found and installed so it can be the one Operating System to rule us all.