Do you want to restore Windows 7 (at some later time), the way you factory-restored vista? The factory restore is linked to oem installs that come with recovery partitions, and can be launched either from within windows or by pressing a key like F11 at boot.
Since you dont have a factory installed Windows 7, its not possible to do a factory restore. But you can image the system drive with a free program like macrium reflect, then restore from the image. That way, you'll be back to the current state with the OS,
drivers and apps already installed. Neither will any re-activation be required.