So my Mom has a laptop with Windows 10 that got a free upgrade key. However, it is quite slow, so I was thinking of replacing the 5400rpm HDD with a cheap SSD I've got lying around. However, if I did a fresh install of Windows 10 on it, would it still automatically activate and see it as the same computer? I think it would since I read the key is tied to the motherboard, but I want to make sure before I try.
AFAIK, Windows' activation isn't tied to the HD. You might be able to re-install Windows 10 and it could activate itself. Try this: Remove the 5400rpm HD and keep it safe. Install the SSD and install Windows 10 on it, a clean install. After the install process completes, wait a few minutes, update the OS, then reboot. It should be activated by now. If it is activated, then just copy whatever you want from the HD
Brandonn2010, That is OK. But an easier method would be to image the current drive and restore the image to the SSD. All drivers, software, updates, data and tweaks will still be installed. It's likely the HD is the "slow" issue and not the OS.