A AcerASUS117 Reputable Feb 14, 2016 15 0 4,510 0 Feb 14, 2016 #1 I bought a laptop with windows 8 on it and now I want to build a computer. I don't want to pay $100 for windows so I want to use my old windows key. Is there any way for me to reuse the old key? How would it work? Can I still use the old hard drive?