Windows: ProduKey is a handy utility for backing up and retrieving the software keys for Windows and Microsoft Office. But what do you do if your computer has already crashed? You can still recover the keys from the broken computer's hard drive.
How To Geek offers a couple of ways to get those software keys. You can remove the drive and, with a hard drive connector or external hard drive case, connect it to another Windows computer. Or you can use a live Linux USB drive to boot the broken computer and copy the config folder from Windows' system folder to the USB drive. Then, on the second computer, run ProduKey and choose the option to load the product keys from the external drive.
It's also a good opportunity to save the text file generated with the product keys. See the full instructions via the link below. ProduKey also can back up or retrieve the keys for Exchange Server and SQL Server.