So I had an older computer running windows 7. I recently decided to buy a bunch of new parts (motherboard, cpu, gpu, power supply) so I could game better. However, understandably, after I upgraded, my OS didn't come with my computer. I had to load a version of Windows 7 on USB just to run my computer. Since I already paid for the OS once for my old computer, is there any way I can transfer it without paying for it again? (They're expensive o_o)