At the screen “Type your product key for activation,” enter your 25-character key exactly as written. You can skip this by clicking “Skip” or “Next” without a key, but then you must enter it within 30 days. For Build 7600, entering it during install is recommended to avoid activation hassles.
If not activated, proceed to Part 4.
You are using an Upgrade key (from Windows Vista or XP) to perform a clean install. product key windows 7 ultimate 64 bit build 7600 install
Understanding Windows 7 Ultimate Build 7600: Installation and Activation At the screen “Type your product key for
Build 7600 is the version of Windows 7, finalized on July 13, 2009. It predates Service Pack 1 (SP1), which is build 7601. If you see "Build 7600" on your system, you are running the original RTM version without SP1. If not activated, proceed to Part 4