Your Windows 10 product key is a special receipt that shows you have an 'activated' copy of Windows.Īll Microsoft Windows operating system versions require the entry of unique product keys during the installation process, as do all versions of Microsoft Office and most other Microsoft retail programs. But without a receipt, how do you prove that you actually own Windows? That's where your product key comes in.
Windows 10 is installed thousands of times a day on computers both new and old.
