It is baffling to me why anyone would buy an Operating System which may last for 20 years or more and not save the installer? The modern way these things are handled is to put all installers into the Downloads file which is backed up at all times.
Even more stunning is how careless some are with Product Keys, which should be treated like currency. Can you really afford to leave $100 bills laying around on desktops or in drawers?
We are not able to link to downloads of the ISO because it encourages piracy. Best to borrow any retail Windows 7 DVD from a friend, extract the ISO to your Downloads file (Hello there!), run the ei.cfg removal tool
if necessary to unlock all versions, burn to DVD or write to flash stick to install your licensed version with Product Key which you have saved.....where?