re: hard drive question

So everyone in this thread is wrong...

Yes, if you transfer the hard drive to a new computer, Windows will indeed detect vastly different hardware and prompt you to re-purchase a license. But ultimately, your EULA allows you to transfer Windows to another machine. If Windows doesn't like the new hardware, you need only contact Microsoft product support to explain what you've done and your key will be revalidated.

The product key is not tied to the motherboard necessarily. It's not tied to the CPU, or the hard drive, or any one thing. Microsoft does not disclose exactly what combination of hardware changes must take place in order to trigger reactivation, but generally it's not about the presence of a particular serial number. For example, replacing your Socket 1150 motherboard with another socket 1150 motherboard probably won't trigger reactivation (but it might). Switching from an Intel platform to an AMD platform most certainly would.