if win7 came with the original computer, it can never be transfer to another. you will have to purchase win7 if you want it on the new computer.
My new computer has WIN8. I want to transfer everything that was on my old WIN7 HD including OS WIN7 to the new computer. I want keep both OS. WIN8 HD has a lot of photos and videos that I have saved. But the OS is really Slow. I really liked how WIN7 ran.