So I was able to find my old gateway pc fx series with i7-920. I took it apart 4 years ago and re-used the hard drive that it had. Now I decided to put it together and use a new Hard drive. It does boot but wont go windows because its a new hard drive the old one is gone. I still have the windows key on the side panel of the computer. How do I reinstall that windows key or add a new windows?