You also may receive a notice to contact the PC manufacture if you have an OEM key that came with your computer, but it can't hurt to try. Please read the information listed below as a possible solution. Additional information and alternative resources:. If you have a friend with a "Retail" version (Full or Upgrade media, just the media as you don't need their key) of the installation DVD (must be the same as your key was for: Home Premium, Pro or Ultimate) it will work with your "Retail" or "OEM" product key if you need to re-install or repair Windows. Read the following Wiki articles: .