I purchased a copy of Windows 8 Pro for my Windows Vista computer and upgraded it. I recently bought a new HP with Windows 8 installed. My question is...if I remove Windows 8 Pro from the old computer can I use it to upgrade my new Windows 8 machine to Pro or do I have to buy Windows 8 Pro Pack. I haven't seen anything if you can use Windows 8 Pro on a computer with Windows 8 already installed. I don't want to lose any of my files, settings, etc. Thanks for everyone's help in advance!!