I have an older PC that originally I had Window 8 (I have Windows 8 install discs). But I took the free update to Windows 10. I've been away from building computers and keeping up on all the latest stuff. But I know there must be a way I could install an SSD for the main OS drive and do a Clean install of Windows 10, even tough I don't have any install discs for Windows 10, nor do I know the Product Key. What to do?