Install and update 1 machine. Run Sysprep on it and shut it down (do not allow it to boot up into the OS again) Then start up the machine with some type of boot disk that allows you to run an imaging tool.

Create an image of the machine. The are a variety of imaging tools on the market. Load subsequent machines from that image instead of from the OEM install disk. Periodically update the 'model' machine and recreate the image to keep the image current. Images of Vista and newer after being Syspreped can be applied to machines where the hardware is not the same with 'reasonable' (but not absolute) success, unlike XP or Server2003R2 and older.

All Time Low So Wrong It's Right Deluxe Edition Download. Search for and study up on WAIK (Win7), it has a different name for Win8, but basically the same product, and also look into WDS (Windows Deployment Services). People with multiple machines to deal with just do not install OS from the original DVD anymore other than to build their 'model' image. Even with new pre-loaded OEM machines I don't use the pre-loaded OS.I create a model image and apply it to all of them.