I have just finished building a new computer and pulled my hard drive out of my old one. It originally had windows vista on it but i purchased and installed windows 7 home premium upgrade. The computer was a 32 bit system. I wanted to start fresh and install it as a 64 bit so i wiped the hard drive using dban. How do i get windows 7 64 bit onto this computer? I am not sure if i have a vista installation disk laying around somewhere. Any help would be greatly appreciated.