I'm currently using Windows 8.1 on my computer, I believe it's an OEM version since I'm using a pre built PC. I recently bought a new motherboard and cpu and wanted to re use my old hard drive. I know I can't use the same OS on the motherboard, but I was wondering if I purchased and downloaded a digital copy of Windows 10 could I just replace my current OS with Windows 10, and then use the hard drive on the new motherboard when I put it in. Would it allow me to reactivate it on the new motherboard? I'd buy a disc version but I'm very far from any stores and I feel like a digital download would be my best option. I also do not have an empty dvd disc, or USB to put the copy of windows on. Sorry if this question is confusing.